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Author |
Lazarevic, N.; Baum, A.; Milosavljevic, A.; Peis, L.; Stumberger, R.; Bekaert, J.; Solajic, A.; Pesic, J.; Wang, A.; Scepanovic, M.; Abeykoon, A.M.M.; Milošević, M.V.; Petrovic, C.; Popovic, Z.V.; Hackl, R. |
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Title |
Evolution of lattice, spin, and charge properties across the phase diagram of Fe1-xSx |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
106 |
Issue |
9 |
Pages |
094510-94519 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
A Raman scattering study covering the entire substitution range of the FeSe1-xSx solid solution is presented. Data were taken as a function of sulfur concentration x for 0 <= x <= 1, of temperature and of scattering symmetry. All types of excitations including phonons, spins, and charges are analyzed in detail. It is observed that the energy and width of the iron-related B-1g phonon mode vary continuously across the entire range of sulfur substitution. The A(1g) chalcogenide mode disappears above x = 0.23 and reappears at a much higher energy for x = 0.69. In a similar way the spectral features appearing at finite doping in A(1g) symmetry vary discontinuously. The magnetic excitation centered at approximately 500 cm(-1) disappears above x = 0.23 where the A(1g) lattice excitations exhibit a discontinuous change in energy. The low-energy mode associated with fluctuations displays maximal intensity at the nematostructural transition and thus tracks the phase boundary. |
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Wos |
000917933500004 |
Publication Date |
2022-09-19 |
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ISSN |
2469-9969; 2469-9950 |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.7 |
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Call Number |
UA @ admin @ c:irua:194397 |
Serial |
7304 |
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Permanent link to this record |
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Author |
Pascucci, F.; Conti, S.; Neilson, D.; Tempère, J.; Perali, A. |
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Title |
Josephson effect as a signature of electron-hole superfluidity in bilayers of van der Waals heterostructures |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
106 |
Issue |
22 |
Pages |
L220503-6 |
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Keywords |
A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT) |
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Abstract |
We investigate a Josephson junction in an electron-hole superfluid in a double-layer transition metal dichalco-genide heterostructure. The observation of a critical tunneling current is a clear signature of superfluidity. In addition, we find the BCS-BEC crossover physics in the narrow barrier region controls the critical current across the entire system. The corresponding critical velocity, which is measurable in this system, has a maximum when the excitations pass from bosonic to fermionic. Remarkably, this occurs for the density at the boundary of the BEC to BCS-BEC crossover regime determined from the condensate fraction. This provides, in a semiconductor system, an experimental way to determine the position of this boundary. |
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Wos |
000903924400007 |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.7 |
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Call Number |
UA @ admin @ c:irua:193402 |
Serial |
7316 |
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Author |
Nulens, L.; Dausy, H.; Wyszynski, M.J.; Raes, B.; Van Bael, M.J.; Milošević, M.V.; Van de Vondel, J. |
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Title |
Metastable states and hidden phase slips in nanobridge SQUIDs |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
106 |
Issue |
13 |
Pages |
134518-134519 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We fabricated an asymmetric nanoscale SQUID consisting of one nanobridge weak link and one Dayem bridge weak link. The current phase relation of these particular weak links is characterized by multivaluedness and linearity. While the latter is responsible for a particular magnetic field dependence of the critical current (so-called vorticity diamonds), the former enables the possibility of different vorticity states (phase winding numbers) existing at one magnetic field value. In experiments the observed critical current value is stochastic in nature, does not necessarily coincide with the current associated with the lowest energy state and critically depends on the measurement conditions. In this paper, we unravel the origin of the observed metastability as a result of the phase dynamics happening during the freezing process and while sweeping the current. Moreover, we employ special measurement protocols to prepare the desired vorticity state and identify the (hidden) phase slip dynamics ruling the detected state of these nanodevices. In order to gain insights into the dynamics of the condensate and, more specifically the hidden phase slips, we performed time-dependent Ginzburg-Landau simulations. |
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Wos |
000904657300007 |
Publication Date |
2022-10-31 |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.7 |
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Call Number |
UA @ admin @ c:irua:193393 |
Serial |
7321 |
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Permanent link to this record |
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Author |
Demiroglu, I.; Sevik, C. |
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Title |
Extraordinary negative thermal expansion of two-dimensional nitrides : a comparative ab initio study of quasiharmonic approximation and molecular dynamics simulations |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
103 |
Issue |
8 |
Pages |
085430 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Thermal expansion behavior of two-dimensional (2D) nitrides and graphene were studied by ab initio molecular dynamics (MD) simulations as well as quasiharmonic approximation (QHA). Anharmonicity of the acoustic phonon modes are related to the unusual negative thermal expansion (NTE) behavior of the nitrides. Our results also hint that direct ab initio MD simulations are a more elaborate method to investigate thermal expansion behavior of 2D materials than the QHA. Nevertheless, giant NTE coefficients are found for h-GaN and h-AlN within the covered temperature range 100-600 K regardless of the chosen computational method. This unusual NTE of 2D nitrides is reasoned with the out-of-plane oscillations related to the rippling behavior of the monolayers. |
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Wos |
000620346100007 |
Publication Date |
2021-02-22 |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:176671 |
Serial |
7956 |
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Permanent link to this record |
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Author |
Chaves, A.; Sousa, G.O.; Khaliji, K.; da Costa, D.R.; Farias, G.A.; Low, T. |
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Title |
Signatures of subband excitons in few-layer black phosphorus |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
103 |
Issue |
16 |
Pages |
165428 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Recent experimental measurements of light absorption in few-layer black phosphorus (BP) revealed a series of high and sharp peaks, interspersed by pairs of lower and broader features. Here, we propose a theoretical model for these excitonic states in few-layer BP within a continuum approach for the in-plane degrees of freedom and a tight-binding approximation that accounts for interlayer couplings. This yields excitonic transitions between different combinations of the subbands created by the coupled BP layers, which leads to a series of high and low oscillator strength excitonic states, consistent with the experimentally observed bright and dark exciton peaks, respectively. The main characteristics of such subband exciton states, as well as the possibility to control their energies and oscillator strengths via applied electric and magnetic fields, are discussed, towards a full understanding of the excitonic spectrum of few-layer BP and its tunability. |
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Wos |
000647175200002 |
Publication Date |
2021-04-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:178384 |
Serial |
8523 |
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Permanent link to this record |