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Author Demiroglu, I.; Sevik, C. url  doi
openurl 
  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
  Year 2021 Publication Physical Review B Abbreviated Journal (up) Phys Rev B  
  Volume 103 Issue 8 Pages 085430  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  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.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000620346100007 Publication Date 2021-02-22  
  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 Open Access OpenAccess  
  Notes Approved Most recent IF: 3.836  
  Call Number UA @ admin @ c:irua:176671 Serial 7956  
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Author Chaves, A.; Sousa, G.O.; Khaliji, K.; da Costa, D.R.; Farias, G.A.; Low, T. url  doi
openurl 
  Title Signatures of subband excitons in few-layer black phosphorus Type A1 Journal article
  Year 2021 Publication Physical Review B Abbreviated Journal (up) Phys Rev B  
  Volume 103 Issue 16 Pages 165428  
  Keywords A1 Journal article; Condensed Matter Theory (CMT)  
  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.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000647175200002 Publication Date 2021-04-28  
  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 Open Access OpenAccess  
  Notes Approved Most recent IF: 3.836  
  Call Number UA @ admin @ c:irua:178384 Serial 8523  
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Author Claes, J.; Partoens, B.; Lamoen, D. pdf  url
doi  openurl
  Title Decoupled DFT-1/2 method for defect excitation energies Type A1 Journal Article
  Year 2023 Publication Physical Review B Abbreviated Journal (up) Phys. Rev. B  
  Volume 108 Issue 12 Pages 125306  
  Keywords A1 Journal Article; Condensed Matter Theory (CMT) ;  
  Abstract The DFT-1/2 method is a band-gap correction with GW precision at a density functional theory (DFT) computational cost. The method was also extended to correct the gap between defect levels, allowing for the calculation of optical transitions. However, this method fails when the atomic character of the occupied and unoccupied defect levels is similar as we illustrate by two examples, the tetrahedral hydrogen interstitial and the negatively charged vacancy in diamond. We solve this problem by decoupling the effect of the occupied and unoccupied defect levels and call this the decoupled DFT-1/2 method for defects.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001089302800003 Publication Date 2023-09-25  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9950 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 3.7 Times cited Open Access Not_Open_Access  
  Notes This work was supported by the FWO (Research Foundation-Flanders), Project No. G0D1721N. This work was performed in part using HPC resources from the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO-Vlaanderen and the Flemish Government department EWI (Economie, Wetenschap & Innovatie). Approved Most recent IF: 3.7; 2023 IF: 3.836  
  Call Number CMT @ cmt @c:irua:201287 Serial 8976  
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