General corner charge formulas in various tetrahedral and cubic space groups

Fuente: arXiv
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Hauptverfasser: Wada, Hidetoshi, Naito, Katsuaki, Ono, Seishiro, Shiozaki, Ken, Murakami, Shuichi
Format: Preprint
Veröffentlicht: 2023
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author Wada, Hidetoshi
Naito, Katsuaki
Ono, Seishiro
Shiozaki, Ken
Murakami, Shuichi
author_facet Wada, Hidetoshi
Naito, Katsuaki
Ono, Seishiro
Shiozaki, Ken
Murakami, Shuichi
contents In some insulators, corner charges are fractionally quantized, due to the topological invariant called a filling anomaly. The previous theories of fractional corner charges have been mostly limited to two-dimensional systems. In three dimensions, only limited cases have been studied. In this study, we derive formulas for the filling anomaly and the corner charge in various crystals with all the tetrahedral and cubic space groups. We discuss that the quantized corner charge requires the crystal shapes to be vertex-transitive polyhedra. We show that the formula of the filling anomaly is universally given by the difference between electronic and ionic charges at the Wyckoff position 1a. The fractional corner charges appear by equally distributing the filling anomaly to all the corners of the crystal. We also derive the k-space formulas for the fractional corner charge. In some cases, the corner charge is not determined solely from the irreps at high-symmetry k-points. In such cases, we introduce a new Z2 topological invariant to determine the corner charge.
format Preprint
id arxiv_https___arxiv_org_abs_2311_15761
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle General corner charge formulas in various tetrahedral and cubic space groups
Wada, Hidetoshi
Naito, Katsuaki
Ono, Seishiro
Shiozaki, Ken
Murakami, Shuichi
Materials Science
Mesoscale and Nanoscale Physics
In some insulators, corner charges are fractionally quantized, due to the topological invariant called a filling anomaly. The previous theories of fractional corner charges have been mostly limited to two-dimensional systems. In three dimensions, only limited cases have been studied. In this study, we derive formulas for the filling anomaly and the corner charge in various crystals with all the tetrahedral and cubic space groups. We discuss that the quantized corner charge requires the crystal shapes to be vertex-transitive polyhedra. We show that the formula of the filling anomaly is universally given by the difference between electronic and ionic charges at the Wyckoff position 1a. The fractional corner charges appear by equally distributing the filling anomaly to all the corners of the crystal. We also derive the k-space formulas for the fractional corner charge. In some cases, the corner charge is not determined solely from the irreps at high-symmetry k-points. In such cases, we introduce a new Z2 topological invariant to determine the corner charge.
title General corner charge formulas in various tetrahedral and cubic space groups
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2311.15761