Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄
Name
Hsu_2019_2D_Mater._6_031004.pdf
Description
Published version
Size
2.28 MB
Format
Adobe PDF
Checksum (MD5)
dcb8a669a0e1ba6287a3064a2608f74a
Author(s)
Ma, Qiong
Gedik, Nuh
Fu, Liang
Xu, Suyang
Date Issued
May 2019
Journal
2D Materials
Publisher
IOP Publishing
Citation
Hsu, Chuang-Han et al. “Purely rotational symmetry-protected topological crystalline insulator α -Bi₄ Br₄.” 2D Materials, 6, 3 (May 2019): 031004 © 2019 The Author(s)
Version
Final published version
Abstract
Rotational-symmetry-protected topological crystalline insulators (TCIs) are expected to host unique boundary modes, in that the surface normal to the rotational axis can feature surface states with 'unpinned' Dirac points, which are not constrained to lie on high symmetry points or lines, but can lie at any general k point in the Brillouin zone. Also, as a higher order bulk boundary correspondence is involved here, a three-dimensional (3D) TCI can support one-dimensional (1D) helical edge states. Using first-principles band structure calculations, we identify the van der Waals material-Bi4Br4 as a purely rotation symmetry protected TCI. We show that the surface of Bi4Br4 exhibits a pair of unpinned topological Dirac fermions which are related to the presence of a two-fold rotation axis. These unpinned Dirac fermions possess an exotic spin texture which will be highly favorable for spin transport, and a band structure that consists of van Hove singularities due to a Lifshitz transition. We also identify 1D topological hinge states along the edges of an-Bi4Br4 rod. We comment on how the predicted topological features in-Bi4Br4 could be accessed experimentally.
MIT Department
MIT Materials Research Laboratory
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution 3.0 unported license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1088/2053-1583/AB1607
