Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies

Abstract We investigate electronic and optical properties of the topological Weyl semimetals TaAs, TaP, NbAs and NbP crystallizing in bct geometry by means of the ab initio density functional theory with spin-orbit interaction within the independent-particle approximation. The small energetical over...

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Autores principales:	Davide Grassano, Olivia Pulci, Adriano Mosca Conte, Friedhelm Bechstedt
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/756d497cd2344f79848ddd6ef2b8cf79
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spelling	oai:doaj.org-article:756d497cd2344f79848ddd6ef2b8cf792021-12-02T12:32:35ZValidity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies10.1038/s41598-018-21465-z2045-2322https://doaj.org/article/756d497cd2344f79848ddd6ef2b8cf792018-02-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-21465-zhttps://doaj.org/toc/2045-2322Abstract We investigate electronic and optical properties of the topological Weyl semimetals TaAs, TaP, NbAs and NbP crystallizing in bct geometry by means of the ab initio density functional theory with spin-orbit interaction within the independent-particle approximation. The small energetical overlap of Ta5d or Nb4d derived conduction and valence bands leads to electron and/or hole pockets near the Fermi energy at the 24 Weyl nodes. The nodes give rise to two-(three-)dimensional Dirac cones for the W 1 (W 2) Weyl type. The band dispersion and occupation near the Weyl nodes determine the infrared optical properties. They are dominated by interband transitions, which lead to a deviation from the expected constant values of the imaginary part of the dielectric function. The resulting polarization anisotropy is also visible in the real part of the optical conductivity, whose lineshape deviates from the expected linearity. The details of the Weyl nodes are discussed in relation to recent ARPES results for TaAs and NbP, and compared with measured optical spectra for TaAs. The spectral features of the anisotropic and tilted Weyl fermions are restricted to low excitation energies above absorption onsets due to the band occupation.Davide GrassanoOlivia PulciAdriano Mosca ConteFriedhelm BechstedtNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-15 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Davide Grassano Olivia Pulci Adriano Mosca Conte Friedhelm Bechstedt Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies
description	Abstract We investigate electronic and optical properties of the topological Weyl semimetals TaAs, TaP, NbAs and NbP crystallizing in bct geometry by means of the ab initio density functional theory with spin-orbit interaction within the independent-particle approximation. The small energetical overlap of Ta5d or Nb4d derived conduction and valence bands leads to electron and/or hole pockets near the Fermi energy at the 24 Weyl nodes. The nodes give rise to two-(three-)dimensional Dirac cones for the W 1 (W 2) Weyl type. The band dispersion and occupation near the Weyl nodes determine the infrared optical properties. They are dominated by interband transitions, which lead to a deviation from the expected constant values of the imaginary part of the dielectric function. The resulting polarization anisotropy is also visible in the real part of the optical conductivity, whose lineshape deviates from the expected linearity. The details of the Weyl nodes are discussed in relation to recent ARPES results for TaAs and NbP, and compared with measured optical spectra for TaAs. The spectral features of the anisotropic and tilted Weyl fermions are restricted to low excitation energies above absorption onsets due to the band occupation.
format	article
author	Davide Grassano Olivia Pulci Adriano Mosca Conte Friedhelm Bechstedt
author_facet	Davide Grassano Olivia Pulci Adriano Mosca Conte Friedhelm Bechstedt
author_sort	Davide Grassano
title	Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies
title_short	Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies
title_full	Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies
title_fullStr	Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies
title_full_unstemmed	Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies
title_sort	validity of weyl fermion picture for transition metals monopnictides taas, tap, nbas, and nbp from ab initio studies
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/756d497cd2344f79848ddd6ef2b8cf79
work_keys_str_mv	AT davidegrassano validityofweylfermionpicturefortransitionmetalsmonopnictidestaastapnbasandnbpfromabinitiostudies AT oliviapulci validityofweylfermionpicturefortransitionmetalsmonopnictidestaastapnbasandnbpfromabinitiostudies AT adrianomoscaconte validityofweylfermionpicturefortransitionmetalsmonopnictidestaastapnbasandnbpfromabinitiostudies AT friedhelmbechstedt validityofweylfermionpicturefortransitionmetalsmonopnictidestaastapnbasandnbpfromabinitiostudies
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Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies

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