Reference : Electronic structure of TiSe2 from a quasi-self-consistent G0W0 approach
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Physics and Materials Science; Computational Sciences
Electronic structure of TiSe2 from a quasi-self-consistent G0W0 approach
Hellgren, Maria [> >]
Baguet, Lucas [> >]
Calandra, Matteo [> >]
Mauri, Francesco [> >]
Wirtz, Ludger mailto [University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Physics and Materials Science (DPHYMS)]
Physical Review. B
American Physical Society
Yes (verified by ORBilu)
[en] charge density waves ; excitonic insulator ; ab-initio electronic structure
[en] n a previous work, it was shown that the inclusion of exact exchange is essential for a first-principles description of both the electronic and the vibrational properties of TiSe2, M. Hellgren et al. [Phys. Rev. Lett. 119, 176401 (2017)]. The GW approximation provides a parameter-free description of screened exchange but is usually employed perturbatively (G0W0), making results more or less dependent on the starting point. In this work, we develop a quasi-self-consistent extension of G0W0 based on the random phase approximation (RPA) and the optimized effective potential of hybrid density functional theory. This approach generates an optimal G0W0 starting point and a hybrid exchange parameter consistent with the RPA. While self-consistency plays a minor role for systems such as Ar, BN, and ScN, it is shown to be crucial for TiS2 and TiSe2. We find the high-temperature phase of TiSe2 to be a semimetal with a band structure in good agreement with experiment. Furthermore, the optimized hybrid functional agrees well with our previous estimate and therefore accurately reproduces the low-temperature charge-density-wave phase.
Fonds National de la Recherche - FnR
FnR ; FNR13376969 > Ludger Wirtz > ACCEPT > Anharmonic And Exchange Interactions In Phonon Spectra > 01/01/2020 > 30/06/2024 > 2018

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