Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides
We show that the previously predicted “cubic Dirac fermion,” composed of six conventional Weyl fermions including three with left-handed and three with right-handed chirality, is realized in a specific, stable solid state system that has been made years ago, but was not appreciated as a “cubically d...
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2017-05-01
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Series: | Physical Review X |
Online Access: | http://doi.org/10.1103/PhysRevX.7.021019 |
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doaj-fff20a4fcbdf436ba66a34e34057d5542020-11-24T22:21:37ZengAmerican Physical SocietyPhysical Review X2160-33082017-05-017202101910.1103/PhysRevX.7.021019Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal MonochalcogenidesQihang LiuAlex ZungerWe show that the previously predicted “cubic Dirac fermion,” composed of six conventional Weyl fermions including three with left-handed and three with right-handed chirality, is realized in a specific, stable solid state system that has been made years ago, but was not appreciated as a “cubically dispersed Dirac semimetal” (CDSM). We identify the crystal symmetry constraints and find the space group P6_{3}/m as one of the two that can support a CDSM, of which the characteristic band crossing has linear dispersion along the principle axis but cubic dispersion in the plane perpendicular to it. We then conduct a material search using density functional theory, identifying a group of quasi-one-dimensional molybdenum monochalcogenide compounds A^{I}(MoX^{VI})_{3} (A^{I}=Na, K, Rb, In, Tl; X^{VI}=S, Se, Te) as ideal CDSM candidates. Studying the stability of the A(MoX)_{3} family reveals a few candidates such as Rb(MoTe)_{3} and Tl(MoTe)_{3} that are predicted to be resilient to Peierls distortion, thus retaining the metallic character. Furthermore, the combination of one dimensionality and metallic nature in this family provides a platform for unusual optical signature—polarization-dependent metallic vs insulating response.http://doi.org/10.1103/PhysRevX.7.021019 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Qihang Liu Alex Zunger |
spellingShingle |
Qihang Liu Alex Zunger Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides Physical Review X |
author_facet |
Qihang Liu Alex Zunger |
author_sort |
Qihang Liu |
title |
Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides |
title_short |
Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides |
title_full |
Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides |
title_fullStr |
Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides |
title_full_unstemmed |
Predicted Realization of Cubic Dirac Fermion in Quasi-One-Dimensional Transition-Metal Monochalcogenides |
title_sort |
predicted realization of cubic dirac fermion in quasi-one-dimensional transition-metal monochalcogenides |
publisher |
American Physical Society |
series |
Physical Review X |
issn |
2160-3308 |
publishDate |
2017-05-01 |
description |
We show that the previously predicted “cubic Dirac fermion,” composed of six conventional Weyl fermions including three with left-handed and three with right-handed chirality, is realized in a specific, stable solid state system that has been made years ago, but was not appreciated as a “cubically dispersed Dirac semimetal” (CDSM). We identify the crystal symmetry constraints and find the space group P6_{3}/m as one of the two that can support a CDSM, of which the characteristic band crossing has linear dispersion along the principle axis but cubic dispersion in the plane perpendicular to it. We then conduct a material search using density functional theory, identifying a group of quasi-one-dimensional molybdenum monochalcogenide compounds A^{I}(MoX^{VI})_{3} (A^{I}=Na, K, Rb, In, Tl; X^{VI}=S, Se, Te) as ideal CDSM candidates. Studying the stability of the A(MoX)_{3} family reveals a few candidates such as Rb(MoTe)_{3} and Tl(MoTe)_{3} that are predicted to be resilient to Peierls distortion, thus retaining the metallic character. Furthermore, the combination of one dimensionality and metallic nature in this family provides a platform for unusual optical signature—polarization-dependent metallic vs insulating response. |
url |
http://doi.org/10.1103/PhysRevX.7.021019 |
work_keys_str_mv |
AT qihangliu predictedrealizationofcubicdiracfermioninquasionedimensionaltransitionmetalmonochalcogenides AT alexzunger predictedrealizationofcubicdiracfermioninquasionedimensionaltransitionmetalmonochalcogenides |
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1716531714770075648 |