| |
Records |
Links |
|
Author |
Andelkovic, M.; Milovanović, S.P.; Covaci, L.; Peeters, F.M. |
|
| |
Title |
Double moiré with a twist : supermoiré in encapsulated graphene |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Nano Letters |
Abbreviated Journal |
Nano Lett |
|
| |
Volume  |
20 |
Issue |
2 |
Pages |
979 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
A periodic spatial modulation, as created by a moire pattern, has been extensively studied with the view to engineer and tune the properties of graphene. Graphene encapsulated by hexagonal boron nitride (hBN) when slightly misaligned with the top and bottom hBN layers experiences two interfering moire patterns, resulting in a so-called supermoire (SM). This leads to a lattice and electronic spectrum reconstruction. A geometrical construction of the nonrelaxed SM patterns allows us to indicate qualitatively the induced changes in the electronic properties and to locate the SM features in the density of states and in the conductivity. To emphasize the effect of lattice relaxation, we report band gaps at all Dirac-like points in the hole doped part of the reconstructed spectrum, which are expected to be enhanced when including interaction effects. Our result is able to distinguish effects due to lattice relaxation and due to the interfering SM and provides a clear picture on the origin of recently experimentally observed effects in such trilayer heterostuctures. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000514255400021 |
Publication Date |
2020-01-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
10.8 |
Times cited |
33 |
Open Access |
OpenAccess |
|
| |
Notes |
; This work was funded by FLAGERA project TRANS2DTMD and the Flemish Science Foundation (FWO-Vl) through a postdoc fellowship for S.P.M. The authors acknowledge useful discussions with W. Zihao and K. Novoselov. ; |
Approved |
Most recent IF: 10.8; 2020 IF: 12.712 |
|
| |
Call Number |
UA @ admin @ c:irua:168685 |
Serial |
6490 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Smeyers, R.; Milošević, M.V.; Covaci, L. |
|
| |
Title |
Strong gate-tunability of flat bands in bilayer graphene due to moiré encapsulation between hBN monolayers |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Nanoscale |
Abbreviated Journal |
|
|
| |
Volume |
15 |
Issue |
9 |
Pages |
4561-4569 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
When using hexagonal boron-nitride (hBN) as a substrate for graphene, the resulting moire pattern creates secondary Dirac points. By encapsulating a multilayer graphene within aligned hBN sheets the controlled moire stacking may offer even richer benefits. Using advanced tight-binding simulations on atomistically-relaxed heterostructures, here we show that the gap at the secondary Dirac point can be opened in selected moire-stacking configurations, and is independent of any additional vertical gating of the heterostructure. On the other hand, gating can broadly tune the gap at the principal Dirac point, and may thereby strongly compress the first moire mini-band in width against the moire-induced gap at the secondary Dirac point. We reveal that in hBN-encapsulated bilayer graphene this novel mechanism can lead to isolated bands flatter than 10 meV under moderate gating, hence presenting a convenient pathway towards electronically-controlled strongly-correlated states on demand. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000933052600001 |
Publication Date |
2023-02-07 |
|
| |
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 |
6.7 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
|
Approved |
Most recent IF: 6.7; 2023 IF: 7.367 |
|
| |
Call Number |
UA @ admin @ c:irua:195249 |
Serial |
7340 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Chaves, A.; Covaci, L.; Peeters, F.M.; Milošević, M.V. |
|
| |
Title |
Topologically protected moiré exciton at a twist-boundary in a van der Waals heterostructure |
Type |
A1 Journal article |
| |
Year |
2022 |
Publication |
2D materials |
Abbreviated Journal |
2D Mater |
|
| |
Volume |
9 |
Issue |
2 |
Pages |
025012 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
A twin boundary in one of the layers of a twisted van der Waals heterostructure separates regions with near opposite inter-layer twist angles. In a MoS<sub>2</sub>/WSe<sub>2</sub>bilayer, the regions with<inline-formula><tex-math><?CDATA $Rh^h$?></tex-math><math overflow=“scroll”><msubsup><mi>R</mi><mi>h</mi><mi>h</mi></msubsup></math><inline-graphic href=“tdmac529dieqn1.gif” type=“simple” /></inline-formula>and<inline-formula><tex-math><?CDATA $Rh^X$?></tex-math><math overflow=“scroll”><msubsup><mi>R</mi><mi>h</mi><mi>X</mi></msubsup></math><inline-graphic href=“tdmac529dieqn2.gif” type=“simple” /></inline-formula>stacking registry that defined the sub-lattices of the moiré honeycomb pattern would be mirror-reflected across such a twist boundary. In that case, we demonstrate that topologically protected chiral moiré exciton states are confined at the twist boundary. These are one-dimensional and uni-directional excitons with opposite velocities for excitons composed by electronic states with opposite valley/spin character, enabling intrinsic, guided, and far reaching valley-polarized exciton currents. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000760518100001 |
Publication Date |
2022-04-01 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2053-1583 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
5.5 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
Fonds Wetenschappelijk Onderzoek; Conselho Nacional de Desenvolvimento Científico e Tecnológico, PQ ; |
Approved |
Most recent IF: 5.5 |
|
| |
Call Number |
CMT @ cmt @c:irua:187124 |
Serial |
7046 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Joao, S.M.; Andelkovic, M.; Covaci, L.; Rappoport, T.G.; Lopes, J.M.V.P.; Ferreira, A. |
|
| |
Title |
KITE : high-performance accurate modelling of electronic structure and response functions of large molecules, disordered crystals and heterostructures |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Royal Society Open Science |
Abbreviated Journal |
Roy Soc Open Sci |
|
| |
Volume |
7 |
Issue |
2 |
Pages |
191809-191832 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
We present KITE, a general purpose open-source tight-binding software for accurate real-space simulations of electronic structure and quantum transport properties of large-scale molecular and condensed systems with tens of billions of atomic orbitals (N similar to 10(10)). KITE's core is written in C++, with a versatile Python-based interface, and is fully optimized for shared memory multi-node CPU architectures, thus scalable, efficient and fast. At the core of KITE is a seamless spectral expansion of lattice Green's functions, which enables large-scale calculations of generic target functions with uniform convergence and fine control over energy resolution. Several functionalities are demonstrated, ranging from simulations of local density of states and photo-emission spectroscopy of disordered materials to large-scale computations of optical conductivity tensors and real-space wave-packet propagation in the presence of magneto-static fields and spin-orbit coupling. On-the-fly calculations of real-space Green's functions are carried out with an efficient domain decomposition technique, allowing KITE to achieve nearly ideal linear scaling in its multi-threading performance. Crystalline defects and disorder, including vacancies, adsorbates and charged impurity centres, can be easily set up with KITE's intuitive interface, paving the way to user-friendly large-scale quantum simulations of equilibrium and non-equilibrium properties of molecules, disordered crystals and heterostructures subject to a variety of perturbations and external conditions. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000518020200001 |
Publication Date |
2020-02-26 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2054-5703 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
3.5 |
Times cited |
19 |
Open Access |
OpenAccess |
|
| |
Notes |
; T.G.R. and A.F. acknowledge support from the Newton Fund and the Royal Society through the Newton Advanced Fellowship scheme (ref. no. NA150043). M.A. and L.C. acknowledge support from the Trans2DTMD FlagEra project and the VSC (Flemish Supercomputer Center). A.F. acknowledges support from the Royal Society through a University Research Fellowship (ref. nos. UF130385 and URF-R-191021) and an Enhancement Award (ref. no. RGF-EA-180276). T.G.R. acknowledges the support from the Brazilian agencies CNPq and FAPERJ and COMPETE2020, PORTUGAL2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) through project POCI-01-0145-FEDER-028114. S.M.J. is supported by Fundacao para a Ciencia e Tecnologia (FCT) under the grant no. PD/BD/142798/ 2018. S.M.J. and J.M.V.P.L. acknowledge financial support from the FCT, COMPETE 2020 programme in FEDER component (European Union), through projects POCI-01-0145-FEDER028887 and UID/FIS/04650/2013. S.M.J. and J.M.V.P.L. further acknowledge financial support from FCT through national funds, co-financed by COMPETE-FEDER (grant no. M-ERANET2/0002/2016 -UltraGraf) under the Partnership Agreement PT2020. ; |
Approved |
Most recent IF: 3.5; 2020 IF: 2.243 |
|
| |
Call Number |
UA @ admin @ c:irua:167751 |
Serial |
6556 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Jorissen, B.; Covaci, L.; Partoens, B. |
|
| |
Title |
Comparative analysis of tight-binding models for transition metal dichalcogenides |
Type |
A1 Journal article |
| |
Year |
2024 |
Publication |
SciPost physics core |
Abbreviated Journal |
|
|
| |
Volume |
7 |
Issue |
1 |
Pages |
004-30 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
We provide a comprehensive analysis of the prominent tight-binding (TB) models for transition metal dichalcogenides (TMDs) available in the literature. We inspect the construction of these TB models, discuss their parameterization used and conduct a thorough comparison of their effectiveness in capturing important electronic properties. Based on these insights, we propose a novel TB model for TMDs designed for enhanced computational efficiency. Utilizing MoS2 as a representative case, we explain why specific models offer a more accurate description. Our primary aim is to assist researchers in choosing the most appropriate TB model for their calculations on TMDs. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
|
Publication Date |
2024-02-06 |
|
| |
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 |
Not_Open_Access |
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
UA @ admin @ c:irua:202983 |
Serial |
9012 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Wang, Z.; Wang, Y.B.; Yin, J.; Tovari, E.; Yang, Y.; Lin, L.; Holwill, M.; Birkbeck, J.; Perello, D.J.; Xu, S.; Zultak, J.; Gorbachev, R.V.; Kretinin, A.V.; Taniguchi, T.; Watanabe, K.; Morozov, S.V.; Andelkovic, M.; Milovanović, S.P.; Covaci, L.; Peeters, F.M.; Mishchenko, A.; Geim, A.K.; Novoselov, K.S.; Fal'ko, V.I.; Knothe, A.; Woods, C.R. |
|
| |
Title |
Composite super-moiré lattices in double-aligned graphene heterostructures = Composite super-moire lattices in double-aligned graphene heterostructures |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
Science Advances |
Abbreviated Journal |
|
|
| |
Volume |
5 |
Issue |
12 |
Pages |
eaay8897 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
When two-dimensional (2D) atomic crystals are brought into close proximity to form a van der Waals heterostructure, neighbouring crystals may influence each other's properties. Of particular interest is when the two crystals closely match and a moire pattern forms, resulting in modified electronic and excitonic spectra, crystal reconstruction, and more. Thus, moire patterns are a viable tool for controlling the properties of 2D materials. However, the difference in periodicity of the two crystals limits the reconstruction and, thus, is a barrier to the low-energy regime. Here, we present a route to spectrum reconstruction at all energies. By using graphene which is aligned to two hexagonal boron nitride layers, one can make electrons scatter in the differential moire pattern which results in spectral changes at arbitrarily low energies. Further, we demonstrate that the strength of this potential relies crucially on the atomic reconstruction of graphene within the differential moire super cell. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
000505069600089 |
Publication Date |
2019-12-21 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2375-2548 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
|
Times cited |
49 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ admin @ c:irua:165754 |
Serial |
6289 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Lin, S.-H.; Milošević, M.V.; Covaci, L.; Janko, B.; Peeters, F.M. |
|
| |
Title |
Quantum rotor in nanostructured superconductors |
Type |
A1 Journal article |
| |
Year |
2014 |
Publication |
Scientific reports |
Abbreviated Journal |
Sci Rep-Uk |
|
| |
Volume |
4 |
Issue |
|
Pages |
4542-4546 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
|
| |
Abstract |
Despite its apparent simplicity, the idealized model of a particle constrained to move on a circle has intriguing dynamic properties and immediate experimental relevance. While a rotor is rather easy to set up classically, the quantum regime is harder to realize and investigate. Here we demonstrate that the quantum dynamics of quasiparticles in certain classes of nanostructured superconductors can be mapped onto a quantum rotor. Furthermore, we provide a straightforward experimental procedure to convert this nanoscale superconducting rotor into a regular or inverted quantum pendulum with tunable gravitational field, inertia, and drive. We detail how these novel states can be detected via scanning tunneling spectroscopy. The proposed experiments will provide insights into quantum dynamics and quantum chaos. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Nature Publishing Group |
Place of Publication |
London |
Editor |
|
|
| |
Language |
|
Wos |
000333555300007 |
Publication Date |
2014-04-01 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2045-2322; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.259 |
Times cited |
4 |
Open Access |
|
|
| |
Notes |
; The work was supported by the Flemish Science Foundation (FWO-Vl), the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract W-31-109-Eng-38, and the US National Science Foundation via NSF-NIRT ECS-0609249. ; |
Approved |
Most recent IF: 4.259; 2014 IF: 5.578 |
|
| |
Call Number |
UA @ lucian @ c:irua:116848 |
Serial |
2785 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Andelkovic, M.; Covaci, L.; Peeters, F.M. |
|
| |
Title |
DC conductivity of twisted bilayer graphene: Angle-dependent transport properties and effects of disorder |
Type |
A1 Journal article |
| |
Year |
2018 |
Publication |
Physical review materials |
Abbreviated Journal |
|
|
| |
Volume |
2 |
Issue |
3 |
Pages |
034004 |
|
| |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
|
| |
Abstract |
The in-plane dc conductivity of twisted bilayer graphene is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding approach the transport properties as a function of rotation angle, applied perpendicular electric field, and vacancy disorder. We find that for high-angle twists, the two layers are effectively decoupled, and the minimum conductivity at the Dirac point corresponds to double the value observed in monolayer graphene. This remains valid even in the presence of vacancies, hinting that chiral symmetry is still preserved. On the contrary, for low twist angles, the conductivity at the Dirac point depends on the twist angle and is not protected in the presence of disorder. Furthermore, for low angles and in the presence of an applied electric field, we find that the chiral boundary states emerging between AB and BA regions contribute to the dc conductivity, despite the appearance of localized states in the AA regions. The results agree qualitatively with recent transport experiments in low-angle twisted bilayer graphene. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
American Physical Society |
Place of Publication |
College Park, Md |
Editor |
|
|
| |
Language |
|
Wos |
000427822700002 |
Publication Date |
2018-03-20 |
|
| |
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 |
27 |
Open Access |
|
|
| |
Notes |
; We acknowledge financial support from the graphene FLAG-ERA project TRANS2DTMD. ; |
Approved |
Most recent IF: NA |
|
| |
Call Number |
UA @ lucian @ c:irua:150838UA @ admin @ c:irua:150838 |
Serial |
4964 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Conti, S.; Chaves, A.; Pandey, T.; Covaci, L.; Peeters, F.M.; Neilson, D.; Milošević, M.V. |
|
| |
Title |
Flattening conduction and valence bands for interlayer excitons in a moire MoS₂/WSe₂ heterobilayer |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Nanoscale |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
1-11 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
|
| |
Abstract |
We explore the flatness of conduction and valence bands of interlayer excitons in MoS2/WSe2 van der Waals heterobilayers, tuned by interlayer twist angle, pressure, and external electric field. We employ an efficient continuum model where the moire pattern from lattice mismatch and/or twisting is represented by an equivalent mesoscopic periodic potential. We demonstrate that the mismatch moire potential is too weak to produce significant flattening. Moreover, we draw attention to the fact that the quasi-particle effective masses around the Gamma-point and the band flattening are reduced with twisting. As an alternative approach, we show (i) that reducing the interlayer distance by uniform vertical pressure can significantly increase the effective mass of the moire hole, and (ii) that the moire depth and its band flattening effects are strongly enhanced by accessible electric gating fields perpendicular to the heterobilayer, with resulting electron and hole effective masses increased by more than an order of magnitude – leading to record-flat bands. These findings impose boundaries on the commonly generalized benefits of moire twistronics, while also revealing alternative feasible routes to achieve truly flat electron and hole bands to carry us to strongly correlated excitonic phenomena on demand. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Wos |
001047512300001 |
Publication Date |
2023-07-25 |
|
| |
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 |
6.7 |
Times cited |
|
Open Access |
Not_Open_Access: Available from 25.01.2024 |
|
| |
Notes |
|
Approved |
Most recent IF: 6.7; 2023 IF: 7.367 |
|
| |
Call Number |
UA @ admin @ c:irua:198290 |
Serial |
8819 |
|
| Permanent link to this record |
