Nonsymmorphic symmetry protected node-line semimetal in the trigonal YH3.
Sci Rep
; 8(1): 1467, 2018 01 23.
Article
em En
| MEDLINE
| ID: mdl-29362498
ABSTRACT
Using ab initio calculations based on density-functional theory and effective model analysis, we propose that the trigonal YH3 (Space Group P[Formula see text]c1) at ambient pressure is a node-line semimetal when spin-orbit coupling (SOC) is ignored. This trigonal YH3 has very clean electronic structure near Fermi level and its nodal lines locate very closely to the Fermi energy, which makes it a perfect system for model analysis. Symmetry analysis shows that the nodal ring in this compound is protected by the glide-plane symmetry, where the band inversion of |Y+, d xz ã and |H1-, sã orbits at Γ point is responsible for the formation of the nodal lines. When SOC is included, the line nodes are prohibited by the glide-plane symmetry, and a small gap (≈5 meV) appears, which leads YH3 to be a strong topological insulator with Z2 indices (1,000). Thus the glide-plane symmetry plays an opposite role in the formation of the nodal lines in cases without and with SOC. As the SOC-induced gap is so small that can be neglected, this P[Formula see text]c1 YH3 may be a good candidate for experimental explorations on the fundamental physics of topological node-line semimetals. We find the surface states of this P[Formula see text]c1 phase are somehow unique and may be helpful to identify the real ground state of YH3 in the experiment.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article