Strain-induced topological phase transition with inversion of the in-plane electric polarization in tiny-gap semiconductor SiGe monolayer
- Authors
- Lee, Kyu Won; Lee, Cheol Eui
- Issue Date
- 9-7월-2020
- Publisher
- NATURE PUBLISHING GROUP
- Citation
- SCIENTIFIC REPORTS, v.10, no.1
- Indexed
- SCIE
SCOPUS
- Journal Title
- SCIENTIFIC REPORTS
- Volume
- 10
- Number
- 1
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/54411
- DOI
- 10.1038/s41598-020-68228-3
- ISSN
- 2045-2322
- Abstract
- Our density functional theory calculations show that tiny-gap semiconductor SiGe monolayer is a quantum valley Hall insulator with a spontaneous electric polarization and, under a small biaxial strain, undergoes a topological phase transition between the states with opposite valley Chern numbers. The topological phase transition entails abrupt inversion of the in-plane electric polarization corresponding to inversion of the sublattice pseudospin polarization, while the out-of-plane electric polarization shows a linear response to the biaxial strain as well as to the perpendicular electric field regardless of the phase transition. Thus, the quantum valley Hall state entails in-plane ferroelectricity corresponding to a sublattice pseudospin ferromagnetism.
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Collections - College of Science > Department of Physics > 1. Journal Articles
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