| |
Records |
Links |
|
Author |
Ribeiro Gomes, R. |
|
| |
Title |
The first order equations for the Ginzburg-Landau theory and the vortex states near a permalloy disk |
Type |
Doctoral thesis |
| |
Year  |
2018 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
220 p. |
|
| |
Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:152233 |
Serial |
5213 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Bizindavyi, J.; Verhulst, A.S.; Sorée, B.; Groeseneken, G. |
|
| |
Title |
Impact of calibrated band-tails on the subthreshold swing of pocketed TFETs |
Type |
P1 Proceeding |
| |
Year |
2018 |
Publication |
Conference digest
T2 – 76th Device Research Conference (DRC), JUN 24-27, 2018, Santa Barbara, CA |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
|
|
| |
Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000444728400086 |
Publication Date |
2018-09-07 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
978-1-5386-3028-0 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:153780 |
Serial |
5217 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Kaintura, A.; Foss, K.; Couckuyt, I.; Dhaene, T.; Zografos, O.; Vaysset, A.; Sorée, B. |
|
| |
Title |
Machine Learning for Fast Characterization of Magnetic Logic Devices |
Type |
P1 Proceeding |
| |
Year |
2018 |
Publication |
(edaps 2018) |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
|
|
| |
Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Non-charge-based logic devices are promising candidates for future logic circuits. Interest in studying and developing these devices has grown dramatically in the past decade as they possess key advantages over conventional CMOS technology. Due to their novel designs, a large number of micromagnetic simulations are required to fully characterize the behavior of these devices. The number and complexity of these simulations place large computational requirements on device development. We use state-of-the-art machine learning techniques to expedite identification of their behavior. Several intelligent sampling strategies are combined with machine learning multi-class classification models. These techniques are applied to a recently developed exchange-driven magnetic logic scheme that utilizes direct exchange coupling as the main driver. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
978-1-5386-6592-3 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:160484 |
Serial |
5219 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Saberi-Pouya, S. |
|
| |
Title |
Many body properties in monolayer and doublelayer black phosphorus |
Type |
Doctoral thesis |
| |
Year |
2018 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
148 p. |
|
| |
Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:151744 |
Serial |
5220 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
De Sloovere, D.; Safari, M.; Elen, K.; D'Haen, J.; Drozhzhin, O.A.; Abakumov, A.M.; Simenas, M.; Banys, J.; Bekaert, J.; Partoens, B.; Van Bael, M.K.; Hardy, A. |
|
| |
Title |
Reduced Na2+xTi4O9 composite : a durable anode for sodium-ion batteries |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
|
| |
Volume |
30 |
Issue |
23 |
Pages |
8521-8527 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Sodium-ion batteries (SIBs) are potential cost-effective solutions for stationary energy storage applications. Unavailability of suitable anode materials, however, is one of the important barriers to the maturity of SIBs. Here, we report a Na2+xTi4O9/C composite as a promising anode candidate for SIBs with high capacity and cycling stability. This anode is characterized by a capacity of 124 mAh g(-1) (plus 11 mAh g(-1) contributed by carbon black), an average discharge potential of 0.9 V vs Na/Na+, a good rate capability and a high stability (89% capacity retention after 250 cycles at a rate of 1 degrees C). The mechanisms of sodium insertion/deinsertion and of the formation of Na2+xTi4O9/C are investigated with the aid of various ex/in situ characterization techniques. The in situ formed carbon is necessary for the formation of the reduced sodium titanate. This synthesis method may enable the convenient synthesis of other composites of crystalline phases with amorphous carbon. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000453489300014 |
Publication Date |
2018-11-29 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0897-4756 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
9.466 |
Times cited |
7 |
Open Access |
|
|
| |
Notes |
; This work was supported by the FWO (Research Foundation Flanders, project G040116). O.A.D. and A.M.A. are grateful to the Russian Science Foundation for financial support (Grant 17-73-30006). The authors acknowledge Pieter Samyn for Raman spectroscopy, Fulya Ulu Okudur for preliminary TEM, Bart Ruttens for XRD, Hilde Pellaers for SEM, Tom Haeldermans for elemental analysis, and Karen Leyssen and Vera Meynen for physisorption measurements. ; |
Approved |
Most recent IF: 9.466 |
|
| |
Call Number |
UA @ admin @ c:irua:156235 |
Serial |
5227 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Verreck, D.; Verhulst, A.S.; Van de Put, M.L.; Sorée, B.; Magnus, W.; Collaert, N.; Mocuta, A.; Groeseneken, G. |
|
| |
Title |
Self-consistent procedure including envelope function normalization for full-zone Schrodinger-Poisson problems with transmitting boundary conditions |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
|
| |
Volume |
124 |
Issue |
20 |
Pages |
204501 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
In the quantum mechanical simulation of exploratory semiconductor devices, continuum methods based on a k.p/envelope function model have the potential to significantly reduce the computational burden compared to prevalent atomistic methods. However, full-zone k.p/envelope function simulation approaches are scarce and existing implementations are not self-consistent with the calculation of the electrostatic potential due to the lack of a stable procedure and a proper normalization of the multi-band envelope functions. Here, we therefore present a self-consistent procedure based on a full-zone spectral k.p/envelope function band structure model. First, we develop a proper normalization for the multi-band envelope functions in the presence of transmitting boundary conditions. This enables the calculation of the free carrier densities. Next, we construct a procedure to obtain self-consistency of the carrier densities with the electrostatic potential. This procedure is stabilized with an adaptive scheme that relies on the solution of Poisson's equation in the Gummel form, combined with successive underrelaxation. Finally, we apply our procedure to homostructure In0.53Ga0.47As tunnel field-effect transistors (TFETs) and staggered heterostructure GaAs0.5Sb0.5/In0.53Ga0.47As TFETs and show the importance of self-consistency on the device predictions for scaled dimensions. Published by AIP Publishing. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000451743900015 |
Publication Date |
2018-11-30 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.068 |
Times cited |
1 |
Open Access |
|
|
| |
Notes |
; This work was supported by imec's Industrial Affiliation Program. ; |
Approved |
Most recent IF: 2.068 |
|
| |
Call Number |
UA @ admin @ c:irua:156291 |
Serial |
5228 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Domingos, J.L.C. |
|
| |
Title |
Study of colloidal systems of anisotropic magnetic particles |
Type |
Doctoral thesis |
| |
Year |
2018 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
114 p. |
|
| |
Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
|
| |
Abstract |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:152284 |
Serial |
5232 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Rezvani, S.J.; Perali, A.; Fretto, M.; De Leo, N.; Flammia, L.; Milošević, M.; Nannarone, S.; Pinto, N. |
|
| |
Title |
Substrate-induced proximity effect in superconducting niobium nanofilms |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Condensed Matter |
Abbreviated Journal |
|
|
| |
Volume |
4 |
Issue |
1 |
Pages |
4 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Structural and superconducting properties of high-quality niobium nanofilms with different thicknesses are investigated on silicon oxide (SiO2) and sapphire substrates. The role played by the different substrates and the superconducting properties of the Nb films are discussed based on the defectivity of the films and on the presence of an interfacial oxide layer between the Nb film and the substrate. The X-ray absorption spectroscopy is employed to uncover the structure of the interfacial layer. We show that this interfacial layer leads to a strong proximity effect, especially in films deposited on a SiO2 substrate, altering the superconducting properties of the Nb films. Our results establish that the critical temperature is determined by an interplay between quantum-size effects, due to the reduction of the Nb film thicknesses, and proximity effects. The detailed investigation here provides reference characterizations and has direct and important implications for the fabrication of superconducting devices based on Nb nanofilms. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000464289300001 |
Publication Date |
2018-12-31 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2410-3896 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
3 |
Open Access |
|
|
| |
Notes |
; This project was financially supported by University of Camerino, FAR project CESEMN. ; |
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:159463 |
Serial |
5233 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Kocabas, T.; Cakir, D.; Gulseren, O.; Ay, F.; Perkgoz, N.K.; Sevik, C. |
|
| |
Title |
A distinct correlation between the vibrational and thermal transport properties of group VA monolayer crystals |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Nanoscale |
Abbreviated Journal |
|
|
| |
Volume |
10 |
Issue |
16 |
Pages |
7803-7812 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The investigation of thermal transport properties of novel two-dimensional materials is crucially important in order to assess their potential to be used in future technological applications, such as thermoelectric power generation. In this respect, the lattice thermal transport properties of the monolayer structures of group VA elements (P, As, Sb, Bi, PAs, PSb, PBi, AsSb, AsBi, SbBi, P3As1, P3Sb1, P1As3, and As3Sb1) with a black phosphorus like puckered structure were systematically investigated by first-principles calculations and an iterative solution of the phonon Boltzmann transport equation. Phosphorene was found to have the highest lattice thermal conductivity, , due to its low average atomic mass and strong interatomic bonding character. As a matter of course, anisotropic was obtained for all the considered materials, owing to anisotropy in frequency values and phonon group velocities calculated for these structures. However, the determined linear correlation between the anisotropy in the values of P, As, and Sb is significant. The results corresponding to the studied compound structures clearly point out that thermal (electronic) conductivity of pristine monolayers might be suppressed (improved) by alloying them with the same group elements. For instance, the room temperature of PBi along the armchair direction was predicted to be as low as 1.5 W m(-1) K-1, whereas that of P was predicted to be 21 W m(-1) K-1. In spite of the apparent differences in structural and vibrational properties, we peculiarly revealed an intriguing correlation between the values of all the considered materials as = c(1) + c(2)/m(2), in particular along the zigzag direction. Furthermore, our calculations on compound structures clearly showed that the thermoelectric potential of these materials can be improved by suppressing their thermal properties. The presence of ultra-low values and high electrical conductivity (especially along the armchair direction) makes this class of monolayers promising candidates for thermoelectric applications. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000431030000054 |
Publication Date |
2018-03-22 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2040-3364; 2040-3372 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193785 |
Serial |
7388 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Tiwari, S.; Van de Put, M.L.; Sorée, B.; Vandenberghe, W.G. |
|
| |
Title |
Carrier transport in a two-dimensional topological insulator nanoribbon in the presence of vacancy defects |
Type |
P1 Proceeding |
| |
Year |
2018 |
Publication |
International Conference on Simulation of Semiconductor Processes and Devices : [proceedings]
T2 – International Conference on Simulation of Semiconductor Processes and, Devices (SISPAD), SEP 24-26, 2018, Austin, TX |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
92-96 |
|
| |
Keywords |
P1 Proceeding; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We model transport through two-dimensional topological insulator (TI) nanoribbons. To model the quantum transport, we employ the non-equilibrium Green's function approach. With the presented approach, we study the effect of lattice imperfections on the carrier transport. We observe that the topologically protected edge states of TIs are robust against a high percentage (2%) of vacancy defects. We also investigate tunneling of the edge states in two decoupled TI nanoribbons. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000516619300024 |
Publication Date |
2018-12-08 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
978-1-5386-6790-3; 1946-1577; 978-1-5386-6791-0 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:181281 |
Serial |
7579 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Kocabas, T.; Ozden, A.; Demiroglu, I.; Cakir, D.; Sevik, C. |
|
| |
Title |
Determination of Dynamically Stable Electrenes toward Ultrafast Charging Battery Applications |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
The journal of physical chemistry letters |
Abbreviated Journal |
|
|
| |
Volume |
9 |
Issue |
15 |
Pages |
4267-4274 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Electrenes, an atomically thin form of layered electrides, are very recent members of the 2D materials family. In this work, we employed first principle calculations to determine stable, exfoliatable, and application-promising 2D electrene materials among possible M2X compounds, where M is a group II-A metal and X is a nonmetal element (C, N, P, As, and Sb). The promise of stable electrene compounds for battery applications is assessed via their exfoliation energy, adsorption properties, and migration energy barriers toward relevant Li, Na, K, and Ca atoms. Our calculations revealed five new stable electrene candidates in addition to previously known Ca2N and Sr2N. Among these seven dynamically stable electrenes, Ba2As, Ba2P, Ba2Sb, Ca2N, Sr2N, and Sr2P are found to be very promising for either K or Na ion batteries due to their extremely low migration energy barriers (5-16 meV), which roughly demonstrates 105 times higher mobility than graphene and two to four times higher mobility than other promising 2D materials such as MXene (Mo2C). |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000440956500020 |
Publication Date |
2018-07-11 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1948-7185 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193765 |
Serial |
7779 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Siriwardane, E.M.D.; Karki, P.; Sevik, C.; Cakir, D. |
|
| |
Title |
Electronic and mechanical properties of stiff rhenium carbide monolayers: A first-principles investigation |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Applied surface science |
Abbreviated Journal |
|
|
| |
Volume |
458 |
Issue |
|
Pages |
762-768 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
In this study, we predicted two new stable metallic Re-C based monolayer structures with a rectangular (r-ReC2) and a hexagonal (h-Re2C) crystal symmetry using first-principle calculations based on density functional theory. Our results obtained from mechanical and phonon calculations and high-temperature molecular dynamic simulations clearly proved the stability of these two-dimensional (2D) crystals. Interestingly, Re-C monolayers in common transition metal carbide structures (i.e. MXenes) were found to be unstable, contrary to expectations. We found that the stable structures, i.e. r-ReC2 and h-Re2C, display superior mechanical properties over the well-known 2D materials. The Young's modulus for r-ReC2 and h-Re2C are extremely high and were calculated as 351 (1310) and 617 (804) N/m (GPa), respectively. Both materials have larger Young's modulus values than the most of the well-known 2D materials. We showed that the combination of the short strong directional p-d bonds, the high coordination number of atoms in the unit-cell and high valence electron density result in strong mechanical properties. Due to its crystal structure, the r-ReC2 monolayer has anisotropic mechanical properties and the crystallographic direction parallel to the C-2 dimers is stiffer compared to perpendicular direction due to strong covalent bonding within C-2 dimers. h-Re2C was derived from the corresponding bulk structure for which we determined the critical thickness for the dynamically stable bulk-derived monolayer structures. In addition, we also investigated the electronic of these two stable structures. Both exhibit metallic behavior and Re-5d orbitals dominate the states around the Fermi level. Due to their ultra high mechanical stability and stiffness, these novel Re-C monolayers can be exploited in various engineering applications. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000441400000088 |
Publication Date |
2018-07-11 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0169-4332 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193776 |
Serial |
7875 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Khazaei, M.; Wang, V.; Sevik, C.; Ranjbar, A.; Arai, M.; Yunoki, S. |
|
| |
Title |
Electronic structures of iMAX phases and their two-dimensional derivatives: A family of piezoelectric materials |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Physical review materials |
Abbreviated Journal |
|
|
| |
Volume |
2 |
Issue |
7 |
Pages |
074002 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Recently, a group of MAX phases, (Mo2/3Y1/3)(2)AlC, (Mo2/3Sc1/3)(2)AlC, (W2/3Sc1/3)(2)AlC,(W2/3Y1/3)(2)AlC, and (V-2/3 Zr-1/3)(2)AlC, with in-plane ordered double transition metals, named iMAX phases, have been synthesized. Experimentally, some of these MAX phases can be chemically exfoliated into two-dimensional (2D) single- or multilayered transition metal carbides, so-called MXenes. Accordingly, the 2D nanostructures derived from iMAX phases are named iMXenes. Here we investigate the structural stabilities and electronic structures of the experimentally discovered iMAX phases and their possible iMXene derivatives. We show that the iMAX phases and their pristine, F, or OH-terminated iMXenes are metallic. However, upon 0 termination, (Mo2/3Y1/3)(2)C, (Mo2/3Sc1/3)(2)C, (W2/3Y1/3)(2)C, and (W2/3Sc1/3)(2)C iMXenes turn into semiconductors. Owing to the absence of centrosymmetry, the semiconducting iMXenes may find applications in piezoelectricity. Our calculations reveal that the semiconducting iMXenes possess giant piezoelectric coefficients as large as 45 x 10(-)(10) C/m. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000438354500001 |
Publication Date |
2018-07-12 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2475-9953 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193791 |
Serial |
7876 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Stosic, D. |
|
| |
Title |
High-performance Ginzburg-Landau simulations of superconductivity |
Type |
Doctoral thesis |
| |
Year |
2018 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
166 p. |
|
| |
Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Superconductivity is one of the most important discoveries of the last century. With many applications in physics, engineering, and technology, superconductors are crucial to our way of living. Several material and engineering issues however prevent their widespread usage in everyday life. Comprehensive studies are being directed at these materials and their properties to come up with new technologies that will address these challenges and enhance their superconductive capabilities. In this context, numerical modeling plays an important role in the search of new solutions to existing material and engineering issues. The time-dependent Ginzburg-Landau (TDGL) theory is a powerful predictive tool for modeling the macroscopic behavior of superconductors. However most of the numerical algorithms developed so far are incapable of describing many basic properties of real superconducting devices, and are too slow on current hardware for large-scale numerical simulations necessary for their accurate description. Therefore, the purpose of this thesis is to develop high-performing numerical solutions that can correctly describe material features to be used as modeling tools of laboratory experiments. Some important innovations introduced in this work include the numerical modeling of nonrectangular geometrical shapes with complex electrical and insulating components, the inclusion of dynamic heating of the material, and the description of different types of material inhomogeneities. These encompass the principal features necessary for a complete description of the superconductive physics in real material samples. In this thesis a numerical solution is developed for modeling superconducting thin films and used to study the superconductive properties of three experimental configurations: the dynamics of vortex matter in a Corbino disk, the motion of ultrafast vortices in an hourglass-shaped microbridge, and the photon detection process in a meander-patterned nanowire. Moreover, a numerical solution is developed for modeling three-dimensional superconductors which are studied here for the first time in the type-I superconducting regime. These numerical algorithms are optimized to exploit the computational horsepower of graphics processing units (GPUs) and multicore central-processing unit (CPU) clusters such that they can achieve high-performance and be used to model large-scale problems previously impossible on conventional machines. Several computational tools are also designed to assist with the modeling of superconducting devices. These include a numerical library of the TDGL equations, a novel mechanism for the generation of complex geometries, a closed-form solver to conduct numerical simulations, and a graphics user interface (GUI) to visualize the dynamic behavior of superconductors. The contributions in this thesis ultimately push the boundaries on what is possible in state-of-the-art numerical modeling of superconductivity. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:181141 |
Serial |
8034 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Demirtas, M.; Odaci, C.; Perkgoz, N.K.; Sevik, C.; Ay, F. |
|
| |
Title |
Low Loss Atomic Layer Deposited Al2O3 Waveguides for Applications in On-Chip Optical Amplifiers |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
IEEE journal of selected topics in quantum electronics |
Abbreviated Journal |
|
|
| |
Volume |
24 |
Issue |
4 |
Pages |
3100508 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We present the growth and optimization of ultralow loss Si-based Al2O3 planar waveguides, which have a high potential to boost the performance of rare-earth ion doped waveguide devices operating at visible and C-band wavelength ranges. The planar waveguide structures are grown using thermal atomic layer deposition. Systematic characterization of the obtained thin films is performed by spectroscopic ellipsometry, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses, and the optimum parameters are identified. The optical loss measurements for both transverse electric (TE) and transverse magnetic polarized light at 633, 829, and 1549 nm are performed. The lowest propagation loss value of 0.04 +/- 0.02 dB/cm for the Al2O3 waveguides for TE polarization at 1549 nm is demonstrated. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000431396300001 |
Publication Date |
2018-04-18 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1077-260x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193780 |
Serial |
8187 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Stosic, D. |
|
| |
Title |
Numerical simulations of magnetic skyrmions in atomically-thin ferromagnetic films |
Type |
Doctoral thesis |
| |
Year |
2018 |
Publication |
|
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
153 p. |
|
| |
Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Moore’s Law has driven the electronics industry for the past half century. However, the doubling of transistors about every two years is beginning to break down, owing to fundamental limits that arise as they approach the atomic length. As a result, the search for new pathways for electronics has become crucial. Among potential candidates, the discovery of magnetic textures known as skyrmions has attracted considerable interest and attention in spintronic technology, which relies on both the electron charge and its spin. The unusual topological and particle-like behavior launched skyrmions into the spotlight of scientific research. Topological protected stability, nanoscale size, and low driving currents needed to move them make skyrmions promising candidates for future consumer nanoelectronics. Recent advances in the field have provided all of the basic functions needed for carrying and processing information. In this thesis, we procure to advance the current understanding of skyrmion physics, and explore their potential to replace conventional electronics technology. First, the fundamental properties and lifetimes of racetrack skyrmions at room temperature are investigated. We discover that skyrmions can easily collapse at the boundary in laterally finite systems, and propose ways to improve their stability for constrained geometries. Then, pinning of single skyrmions on atomic defects of distinct origins are studied. We reveal that the preferred pinning positions depend on the skyrmion size and type of defect being considered, and discuss applications where control of skyrmions by defects is of particular interest. Next, we explore other magnetic configurations that can compete with skyrmions when considering new materials, and describe a previously unseen mechanism for collapse of skyrmions into cycloidal spin backgrounds. Finally, switching and interactions between skyrmions with distinct topologies are reported. We find that skyrmions transition to higher or lower topologies by absorbing a unit spin texture. The interactions between skyrmions of different topological charges can be attractive or repulsive, leading to the formation of arranged clusters. We conclude with a numerical library for simulating magnetic skyrmions in various scenarios. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Additional Links |
UA library record |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:181142 |
Serial |
8322 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Milovanović, S.P.; Peeters, F.M. |
|
| |
Title |
Strained graphene structures : from valleytronics to pressure sensing |
Type |
P1 Proceeding |
| |
Year |
2018 |
Publication |
Nanostructured Materials For The Detection Of Cbrn |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
3-17
T2 - NATO Advanced Research Workshop on Nanos |
|
| |
Keywords |
P1 Proceeding; Pharmacology. Therapy; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Due to its strong bonds graphene can stretch up to 25% of its original size without breaking. Furthermore, mechanical deformations lead to the generation of pseudo-magnetic fields (PMF) that can exceed 300 T. The generated PMF has opposite direction for electrons originating from different valleys. We show that valley-polarized currents can be generated by local straining of multi-terminal graphene devices. The pseudo-magnetic field created by a Gaussian-like deformation allows electrons from only one valley to transmit and a current of electrons from a single valley is generated at the opposite side of the locally strained region. Furthermore, applying a pressure difference between the two sides of a graphene membrane causes it to bend/bulge resulting in a resistance change. We find that the resistance changes linearly with pressure for bubbles of small radius while the response becomes non-linear for bubbles that stretch almost to the edges of the sample. This is explained as due to the strong interference of propagating electronic modes inside the bubble. Our calculations show that high gauge factors can be obtained in this way which makes graphene a good candidate for pressure sensing. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000477758900001 |
Publication Date |
2018-07-11 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
978-94-024-1306-9; 978-94-024-1304-5; 978-94-024-1303-8; 978-94-024-1303-8 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
6 |
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:161972 |
Serial |
8583 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Sarikurt, S.; Çakir, D.; Keceli, M.; Sevik, C. |
|
| |
Title |
The influence of surface functionalization on thermal transport and thermoelectric properties of MXene monolayers |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Nanoscale |
Abbreviated Journal |
|
|
| |
Volume |
10 |
Issue |
18 |
Pages |
8859-8868 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The newest members of a two-dimensional material family, involving transition metal carbides and nitrides (called MXenes), have garnered increasing attention due to their tunable electronic and thermal properties depending on the chemical composition and functionalization. This flexibility can be exploited to fabricate efficient electrochemical energy storage (batteries) and energy conversion (thermoelectric) devices. In this study, we calculated the Seebeck coefficients and lattice thermal conductivity values of oxygen terminated M2CO2 (where M = Ti, Zr, Hf, Sc) monolayer MXene crystals in two different functionalization configurations (model-II (MD-II) and model-III (MD-III)), using density functional theory and Boltzmann transport theory. We estimated the thermoelectric figure-of-merit, zT, of these materials by two different approaches, as well. First of all, we found that the structural model (i.e. adsorption site of oxygen atom on the surface of MXene) has a paramount impact on the electronic and thermoelectric properties of MXene crystals, which can be exploited to engineer the thermoelectric properties of these materials. The lattice thermal conductivity kappa(l), Seebeck coefficient and zT values may vary by 40% depending on the structural model. The MD-III configuration always has the larger band gap, Seebeck coefficient and zT, and smaller kappa(l) as compared to the MD-II structure due to a larger band gap, highly flat valence band and reduced crystal symmetry in the former. The MD-III configuration of Ti2CO2 and Zr2CO2 has the lowest kappa(l) as compared to the same configuration of Hf2CO2 and Sc2CO2. Among all the considered structures, the MD-II configuration of Hf2CO2 has the highest kappa(l), and Ti2CO2 and Zr2CO2 in the MD-III configuration have the lowest kappa(l). For instance, while the band gap of the MD-II configuration of Ti2CO2 is 0.26 eV, it becomes 0.69 eV in MD-III. The zT(max) value may reach up to 1.1 depending on the structural model of MXene. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000432096400055 |
Publication Date |
2018-04-06 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2040-3364; 2040-3372 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193788 |
Serial |
8654 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Mobaraki, A.; Kandemir, A.; Yapicioglu, H.; Gulseren, O.; Sevik, C. |
|
| |
Title |
Validation of inter-atomic potential for WS2 and WSe2 crystals through assessment of thermal transport properties |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Computational materials science |
Abbreviated Journal |
|
|
| |
Volume |
144 |
Issue |
|
Pages |
92-98 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
In recent years, transition metal dichalcogenides (TMDs) displaying astonishing properties are emerged as a new class of two-dimensional layered materials. The understanding and characterization of thermal transport in these materials are crucial for efficient engineering of 2D TMD materials for applications such as thermoelectric devices or overcoming general overheating issues. In this work, we obtain accurate Stillinger-Weber type empirical potential parameter sets for single-layer WS2 and WSe2 crystals by utilizing particle swarm optimization, a stochastic search algorithm. For both systems, our results are quite consistent with first-principles calculations in terms of bond distances, lattice parameters, elastic constants and vibrational properties. Using the generated potentials, we investigate the effect of temperature on phonon energies and phonon linewidth by employing spectral energy density analysis. We compare the calculated frequency shift with respect to temperature with corresponding experimental data, clearly demonstrating the accuracy of the generated inter-atomic potentials in this study. Also, we evaluate the lattice thermal conductivities of these materials by means of classical molecular dynamics simulations. The predicted thermal properties are in very good agreement with the ones calculated from first-principles. (C) 2017 Elsevier B.V. All rights reserved. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000424902300013 |
Publication Date |
2017-12-16 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0927-0256 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
|
Open Access |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:193774 |
Serial |
8729 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Stosic, D.; Mulkers, J.; Van Waeyenberge, B.; Ludermir, T.B.; Milošević, M.V. |
|
| |
Title |
Paths to collapse for isolated skyrmions in few-monolayer ferromagnetic films |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
95 |
Issue |
21 |
Pages |
214418 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Magnetic skyrmions are topological spin configurations in materials with chiral Dzyaloshinskii-Moriya interaction (DMI), that are potentially useful for storing or processing information. To date, DMI has been found in few bulk materials, but can also be induced in atomically thin magnetic films in contact with surfaces with large spin-orbit interactions. Recent experiments have reported that isolated magnetic skyrmions can be stabilized even near room temperature in few-atom-thick magnetic layers sandwiched between materials that provide asymmetric spin-orbit coupling. Here we present the minimum-energy path analysis of three distinct mechanisms for the skyrmion collapse, based on ab initio input and the performed atomic-spin simulations. We focus on the stability of a skyrmion in three atomic layers of Co, either epitaxial on the Pt(111) surface or within a hybrid multilayer where DMI nontrivially varies per monolayer due to competition between different symmetry breaking from two sides of the Co film. In laterally finite systems, their constrained geometry causes poor thermal stability of the skyrmion toward collapse at the boundary, which we show to be resolved by designing the high-DMI structure within an extended film with lower or no DMI. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000404015500001 |
Publication Date |
2017-06-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
48 |
Open Access |
|
|
| |
Notes |
This work was supported by the Research Foundation, Flanders (FWO-Vlaanderen) and Brazilian agency CNPq (Grants No. 442668/2014-7 and No. 140840/2016-8). |
Approved |
Most recent IF: 3.836 |
|
| |
Call Number |
CMT @ cmt @c:irua:144865 |
Serial |
4704 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Callewaert, V.; Saniz, R.; Barbiellini, B.; Bansil, A.; Partoens, B. |
|
| |
Title |
Application of the weighted-density approximation to the accurate description of electron-positron correlation effects in materials |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
96 |
Issue |
8 |
Pages |
085135 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
We discuss positron-annihilation lifetimes for a set of illustrative bulk materials within the framework of the weighted-density approximation (WDA). The WDA can correctly describe electron-positron correlations in strongly inhomogeneous systems, such as surfaces, where the applicability of (semi-)local approximations is limited. We analyze the WDA in detail and show that the electrons which cannot screen external charges efficiently, such as the core electrons, cannot be treated accurately via the pair correlation of the homogeneous electron gas. We discuss how this problem can be addressed by reducing the screening in the homogeneous electron gas by adding terms depending on the gradient of the electron density. Further improvements are obtained when core electrons are treated within the LDA and the valence electron using the WDA. Finally, we discuss a semiempirical WDA-based approach in which a sum rule is imposed to reproduce the experimental lifetimes. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000408342600003 |
Publication Date |
2017-08-24 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
Fonds Wetenschappelijk Onderzoek, G. 0224.14N ; U.S. Department of Energy, DE-FG02-07ER46352 DE-AC02-05CH11231 DE-SC0012575 ; |
Approved |
Most recent IF: 3.836 |
|
| |
Call Number |
CMT @ cmt @c:irua:145703 |
Serial |
4703 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Matsubara, M.; Saniz, R.; Partoens, B.; Lamoen, D. |
|
| |
Title |
Doping anatase TiO2with group V-b and VI-b transition metal atoms: a hybrid functional first-principles study |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
|
| |
Volume |
19 |
Issue |
19 |
Pages |
1945-1952 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
We investigate the role of transition metal atoms of group V-b (V, Nb, Ta) and VI-b (Cr, Mo, W) as n- or p-type dopants in anatase TiO$2$ using thermodynamic
principles and density functional theory with the Heyd-Scuseria-Ernzerhof HSE06 hybrid functional. The HSE06 functional provides a realistic value for the band gap, which ensures a correct classification of dopants as shallow or deep donors or acceptors. Defect formation energies and thermodynamic transition levels are calculated taking into account the constraints imposed by the stability of TiO$2$ and the solubility limit of the impurities.
Nb, Ta, W and Mo are identified as shallow donors. Although W provides two electrons, Nb and Ta show a considerable lower formation energy, in particular under O-poor conditions. Mo donates in principle one electron, but under specific conditions can turn into a double donor. V impurities are deep donors and Cr
shows up as an amphoteric defect, thereby acting as an electron trapping center in n-type TiO$_2$ especially under O-rich conditions. A comparison with the available experimental data yields excellent agreement. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000394426400027 |
Publication Date |
2016-12-12 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1463-9076 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.123 |
Times cited |
19 |
Open Access |
OpenAccess |
|
| |
Notes |
We gratefully acknowledge financial support from the IWTVlaanderenthrough projects G.0191.08 and G.0150.13, and the BOF-NOI of the University of Antwerp. This work was carried out using the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, which is funded by the Hercules foundation. M. M. acknowledges financial support from the GOA project ‘‘XANES meets ELNES’’ of the University of Antwerp. |
Approved |
Most recent IF: 4.123 |
|
| |
Call Number |
EMAT @ emat @ c:irua:140835 |
Serial |
4421 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Callewaert, V.; Saniz, R.; Barbiellini, B.; Partoens, B. |
|
| |
Title |
Surface states and positron annihilation spectroscopy: results and prospects from a first-principles approach |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
|
|
| |
Volume |
791 |
Issue |
791 |
Pages |
012036 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The trapping of positrons at the surface of a material can be exploited to study quite selectively the surface properties of the latter by means of positron annihilation spectroscopy techniques. To support these, it is desirable to be able to theoretically predict the existence of such positronic surface states and to describe their annihilation characteristics with core or valence surface electrons in a reliable way. Here, we build on the well-developed first-principles techniques for the study of positrons in bulk solids as well as on previous models for surfaces, and investigate two schemes that can improve the theoretical description of the interaction of positrons with surfaces. One is based on supplementing the local-density correlation potential with the corrugated image potential at the surface, and the other is based on the weighted-density approximation to correlation. We discuss our results for topological insulators, graphene layers, and quantum dots, with emphasis on the information that can be directly related to experiment. We also discuss some open theoretical problems that should be addressed by future research. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000400610500036 |
Publication Date |
2017-02-22 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1742-6588 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
1 |
Open Access |
|
|
| |
Notes |
We acknowledge financial support from FWO-Vlaanderen (projects G.0150.13 and G.0224.14N). This work was carried out using the HPC infrastructure of the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center (VSC), funded by the Hercules foundation and the Flemish Government (EWI Department). The work at Northeastern University was supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences grant number DE-FG02-07ER46352 (core research), and benefited from Northeastern University’s Advanced Scientific Computation Center (ASCC), the NERSC supercomputing center through DOE grant number DE-AC02- 05CH11231, and support (applications to layered materials) from the DOE EFRC: Center for the Computational Design of Functional Layered Materials (CCDM) under DE-SC0012575. |
Approved |
Most recent IF: NA |
|
| |
Call Number |
CMT @ cmt @ c:irua:140847 |
Serial |
4425 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Eijt, S.W.H.; Shi, W.; Mannheim, A.; Butterling, M.; Schut, H.; Egger, W.; Dickmann, M.; Hugenschmidt, C.; Shakeri, B.; Meulenberg, R.W.; Callewaert, V.; Saniz, R.; Partoens, B.; Barbiellini, B.; Bansil, A.; Melskens, J.; Zeman, M.; Smets, A.H.M.; Kulbak, M.; Hodes, G.; Cahen, D.; Brück, E. |
|
| |
Title |
New insights into the nanostructure of innovative thin film solar cells gained by positron annihilation spectroscopy |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Journal of physics : conference series |
Abbreviated Journal |
|
|
| |
Volume |
791 |
Issue |
791 |
Pages |
012021 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Recent studies showed that positron annihilation methods can provide key insights into the nanostructure and electronic structure of thin film solar cells. In this study, positron annihilation lifetime spectroscopy (PALS) is applied to investigate CdSe quantum dot (QD) light absorbing layers, providing evidence of positron trapping at the surfaces of the QDs. This enables one to monitor their surface composition and electronic structure. Further, 2D-Angular Correlation of Annihilation Radiation (2D-ACAR) is used to investigate the nanostructure of divacancies in photovoltaic-high-quality a-Si:H films. The collected momentum distributions were converted by Fourier transformation to the direct space representation of the electron-positron autocorrelation function. The evolution of the size of the divacancies as a function of hydrogen dilution during deposition of a-Si:H thin films was examined. Finally, we present a first positron Doppler Broadening of Annihilation Radiation (DBAR) study of the emerging class of highly efficient thin film solar cells based on perovskites. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000400610500021 |
Publication Date |
2017-02-22 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1742-6588 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
1 |
Open Access |
|
|
| |
Notes |
The work at Delft University of Technology was supported by the China Scholarship Council (CSC) grant of W.S., by ADEM, A green Deal in Energy Materials of the Ministry of Economic Affairs of The Netherlands (www.adem- innovationlab.nl), and the STW Vidi grant of A.S., Grant No. 10782. The PALS study is based upon experiments performed at the PLEPS instrument of the NEPOMUC facility at the Heinz Maier-Leibnitz Zentrum (MLZ), Garching, Germany, and was supported by the European Commission under the 7 th Framework Programme, Key Action: Strengthening the European Research Area, Research Infrastructures, Contract No. 226507, NMI3. The work at University of Maine was supported by the National Science Foundation under Grant No. DMR-1206940. Research at the University of Antwerp was supported by FWO grants G022414N and G015013. The work at Northeastern University was supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences grant number DE-FG02-07ER46352 (core research), and benefited from Northeastern University's Advanced Scientific Computation Center (ASCC), the NERSC supercomputing center through DOE grant number DE-AC02-05CH11231, and support (applications to layered materials) from the DOE EFRC: Center for the Computational Design of Functional Layered Materials (CCDM) under DE-SC0012575. The work at the Weizmann Institute was supported by the Sidney E. Frank Foundation through the Israel Science Foundation, by the Israel Ministry of Science, and the Israel National Nano-Initiative. D.C. holds the Sylvia and Rowland Schaefer Chair in Energy Research. |
Approved |
Most recent IF: NA |
|
| |
Call Number |
CMT @ cmt @ c:irua:140850 |
Serial |
4426 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Rahemi, V.; Sarmadian, N.; Anaf, W.; Janssens, K.; Lamoen, D.; Partoens, B.; De Wael, K. |
|
| |
Title |
Unique opto-electronic structure and photo reduction properties of sulfur doped lead chromates explaining their instability in paintings |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
|
| |
Volume |
89 |
Issue |
89 |
Pages |
3326-3334 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
|
| |
Abstract |
Chrome yellow refers to a group of synthetic inorganic pigments that became popular as an artists material from the second quarter of the 19th century. The color of the pigment, in which the chromate ion acts as a chromophore, is related to its chemical composition (PbCr1-xSxO4, with 0≤x≤0.8) and crystalline structure (monoclinic/orthorhombic). Their shades range from the yellow-orange to the paler yellow tones with increasing sulfate amount. These pigments show remarkable signs of degradation after limited time periods. Pure PbCrO4 (crocoite in its natural form) has a deep yellow color and is relatively stable, while the co-precipitate with lead sulfate (PbCr1-xSxO4) has a paler shade and seems to degrade faster. This degradation is assumed to be related to the reduction of Cr(VI) to Cr(III). We show that on increasing the sulfur(S)-content in chrome yellow, the band gap increases. Typically, when increasing the band gap, one might assume that a decrease in photo activity is the result. However, the photo activity relative to the Cr content, and thus Cr reduction, of sulfur-rich PbCr1-xSxO4 is found to be much higher compared to the sulfur-poor or non-doped lead chromates. This discrepancy can be explained by the evolution of the crystal and electronic structure as function of the sulfur content: first-principles density functional theory calculations show that both the absorption coefficient and reflection coefficients of the lead chromates change as a result of the sulfate doping in such a way that the generation of electron-hole pairs under illumination relative to the total Cr content increases. These changes in the material properties explain why paler shade yellow colors of this pigment are more prone to discoloration. The electronic structure calculations also demonstrate that lead chromate and its co-precipitates are p-type semiconductors, which explains the observed reduction reaction. As understanding this phenomenon is valuable in the field of cultural heritage, this study is the first joint action of photo-electrochemical measurements and first-principles calculations to approve the higher tendency of sulfur-rich lead chromates to darken. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
|
| |
Language |
|
Wos |
000397478300015 |
Publication Date |
2017-02-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0003-2700 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.32 |
Times cited |
7 |
Open Access |
OpenAccess |
|
| |
Notes |
; The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the Hercules Foundation and the Flemish Government, department EWI. The BOF-GOA action SOLARPAINT of the University of Antwerp Research Council is acknowledged for financial support. W.A. acknowledges support from BELSPO project S2-ART. Dr. L. Monico and Dr. C. Miliani (ISTM, Perugia) are gratefully acknowledged for helpful discussions and for providing some of the initial batches of the materials studied. ; |
Approved |
Most recent IF: 6.32 |
|
| |
Call Number |
UA @ lucian @ c:irua:140886 |
Serial |
4451 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Moors, K.; Sorée, B.; Magnus, W. |
|
| |
Title |
Resistivity scaling in metallic thin films and nanowires due to grain boundary and surface roughness scattering |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Microelectronic engineering |
Abbreviated Journal |
Microelectron Eng |
|
| |
Volume |
167 |
Issue |
167 |
Pages |
37-41 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
A modeling approach, based on an analytical solution of the semiclassical multi-subband Boltzmann transport equation, is presented to study resistivity scaling in metallic thin films and nanowires due to grain boundary and surface roughness scattering. While taking into account the detailed statistical properties of grains, roughness and barrier material as well as the metallic band structure and quantum mechanical aspects of scattering and confinement, the model does not rely on phenomenological fitting parameters. (C) 2016 Elsevier B.V. All rights reserved. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
|
| |
Language |
|
Wos |
000390746000008 |
Publication Date |
2016-10-20 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0167-9317 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
1.806 |
Times cited |
6 |
Open Access |
|
|
| |
Notes |
; ; |
Approved |
Most recent IF: 1.806 |
|
| |
Call Number |
UA @ lucian @ c:irua:140354 |
Serial |
4460 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Milovanovic, S.P.; Peeters, F.M. |
|
| |
Title |
Strained graphene Hall bar |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
|
| |
Volume |
29 |
Issue |
29 |
Pages |
075601 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The effects of strain, induced by a Gaussian bump, on the magnetic field dependent transport properties of a graphene Hall bar are investigated. The numerical simulations are performed using both classical and quantum mechanical transport theory and we found that both approaches exhibit similar characteristic features. The effects of the Gaussian bump are manifested by a decrease of the bend resistance, RB, around zero-magnetic field and the occurrence of side-peaks in RB. These features are explained as a consequence of bump-assisted scattering of electrons towards different terminals of the Hall bar. Using these features we are able to give an estimate of the size of the bump. Additional oscillations in RB are found in the quantum description that are due to the population/depopulation of Landau levels. The bump has a minor influence on the Hall resistance even for very high values of the pseudo-magnetic field. When the bump is placed outside the center of the Hall bar valley polarized electrons can be collected in the leads. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000391584900001 |
Publication Date |
2016-12-24 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0953-8984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
2.649 |
Times cited |
12 |
Open Access |
|
|
| |
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE within the project CONGRAN. ; |
Approved |
Most recent IF: 2.649 |
|
| |
Call Number |
UA @ lucian @ c:irua:140381 |
Serial |
4464 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Li, L.L.; Moldovan, D.; Vasilopoulos, P.; Peeters, F.M. |
|
| |
Title |
Aharonov-Bohm oscillations in phosphorene quantum rings |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
95 |
Issue |
20 |
Pages |
205426 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The Aharonov-Bohm (AB) effect in square phosphorene quantum rings, with armchair and zigzag edges, is investigated using the tight-binding method. The energy spectra and wave functions of such rings, obtained as a function of the magnetic flux Phi threading the ring, are strongly influenced by the ringwidthW, an in-plane electric field E-p, and a side-gating potential V-g. Compared to a square dot, the ring shows an enhanced confinement due to its inner edges and an interedge coupling along the zigzag direction, both of which strongly affect the energy spectrum and the wave functions. The energy spectrum that is gapped consists of a regular part, of conduction (valence) band states, that shows the usual AB oscillations in the higher-(lower-) energy region, and of edge states, in the gap, that exhibit no AB oscillations. As the width W decreases, the AB oscillations become more distinct and regular and their period is close to Phi(0)/2, where the flux quantum Phi(0) = h/e is the period of an ideal circular ring (W -> 0). Both the electric field E-p and the side-gating potential V-g reduce the amplitude of the AB oscillations. The amplitude can be effectively tuned by E-p or V-g and exhibits an anisotropic behavior for different field directions or side-gating configurations. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
|
|
| |
Language |
|
Wos |
000402003700010 |
Publication Date |
2017-05-23 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
|
|
| |
Notes |
; This work was financially supported by the Chinese Academy of Sciences, the Flemish Science Foundation (FWO-V1), and by the Canadian NSERC Grant No. OGP0121756 (P.V.). ; |
Approved |
Most recent IF: 3.836 |
|
| |
Call Number |
UA @ lucian @ c:irua:144267 |
Serial |
4638 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Dabaghmanesh, S.; Saniz, R.; Neyts, E.; Partoens, B. |
|
| |
Title |
Sulfur-alloyed Cr2O3: a new p-type transparent conducting oxide host |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
RSC advances |
Abbreviated Journal |
Rsc Adv |
|
| |
Volume |
7 |
Issue |
7 |
Pages |
4453-4459 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
Doped Cr2O3 has been shown to be a p-type transparent conducting oxide (TCO). Its conductivity, however, is low. As for most p-type TCOs, the main problem is the high effective hole mass due to flat valence bands. We use first-principles methods to investigate whether one can increase the valence band dispersion (i.e. reduce the hole mass) by anion alloying with sulfur, while keeping the band gap large enough for transparency. The alloying concentrations considered are given by Cr(4)SxO(6-x), with x = 1-5. To be able to describe the electronic properties of these materials accurately, we first study Cr2O3, examining critically the accuracy of different density functionals and methods, including PBE, PBE+U, HSE06, as well as perturbative approaches within the GW approximation. Our results demonstrate that Cr4S2O4 has an optical band gap of 3.08 eV and an effective hole mass of 1.8 m(e). This suggests Cr4S2O4 as a new p-type TCO host candidate. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000393751300030 |
Publication Date |
2017-01-16 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2046-2069 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.108 |
Times cited |
9 |
Open Access |
OpenAccess |
|
| |
Notes |
; This work was supported by SIM vzw, Technologiepark 935, BE-9052 Zwijnaarde, Belgium, within the InterPoCo project of the H-INT-S horizontal program. The computational resources and services used in this work were provided by the Vlaams Supercomputer Centrum (VSC) and the HPC infrastructure of the University of Antwerp. ; |
Approved |
Most recent IF: 3.108 |
|
| |
Call Number |
UA @ lucian @ c:irua:141543 |
Serial |
4528 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Mulkers, J.; Van Waeyenberge, B.; Milošević, M.V. |
|
| |
Title |
Effects of spatially engineered Dzyaloshinskii-Moriya interaction in ferromagnetic films |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
95 |
Issue |
95 |
Pages |
144401 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The Dzyaloshinskii-Moriya interaction (DMI) is a chiral interaction that favors formation of domain walls. Recent experiments and ab initio calculations show that there are multiple ways to modify the strength of the interfacially induced DMI in thin ferromagnetic films with perpendicular magnetic anisotropy. In this paper we reveal theoretically the effects of spatially varied DMI on the magnetic state in thin films. In such heterochiral 2D structures we report several emergent phenomena, ranging from the equilibrium spin canting at the interface between regions with different DMI, over particularly strong confinement of domain walls and skyrmions within high-DMI tracks, to advanced applications such as domain tailoring nearly at will, design of magnonic waveguides, and much improved skyrmion racetrack memory. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000399382100003 |
Publication Date |
2017-04-03 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.836 |
Times cited |
60 |
Open Access |
|
|
| |
Notes |
Fonds Wetenschappelijk Onderzoek, G098917N ; |
Approved |
Most recent IF: 3.836 |
|
| |
Call Number |
CMT @ cmt @ c:irua:141917 |
Serial |
4534 |
|
| Permanent link to this record |
