Topological Phase Transition in Quasi-One-Dimensional Bismuth Iodide Bi4I4

The exploration of topological quantum materials and topological phase transitions is at the forefront of modern condensed matter physics. Quasi-one-dimensional (quasi-1D) bismuth iodide Bi4I4 exhibits versatile topological phases of matter including weak topological insulator (WTI) and higher-order...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2024-07
Main Authors: Zhao, W X, Yang, M, X Du, Li, Y D, Zhai, K Y, Hu, Y Q, Han, J F, Huang, Y, Liu, Z K, Yao, Y G, Zhuang, J C, Y Du, Zhou, J J, Chen, Y L, Yang, L X
Format: Article
Language:English
Subjects:
Bismuth
Condensed matter physics
Electronic structure
Energy gap
Fermions
High temperature
Laser applications
Low temperature
Phase transitions
Photoelectric emission
Room temperature
Spatial resolution
Topological insulators
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The exploration of topological quantum materials and topological phase transitions is at the forefront of modern condensed matter physics. Quasi-one-dimensional (quasi-1D) bismuth iodide Bi4I4 exhibits versatile topological phases of matter including weak topological insulator (WTI) and higher-order topological insulator (HOTI) phases with high tunability in response to external parameters. In this work, performing laser-based angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES), we comprehensively investigate the fine electronic structure and topological phase transition of Bi4I4. Our examination of the low-temperature {\alpha}-phase reveals the presence of an energy gap on the (100) surface, providing spectroscopic evidence for the HOTI phase. Conversely, the high-temperature {\beta}-Bi4I4 harbors a gapless Dirac fermion on the (100) surface alongside gapped states on the (001) surface, thereby establishing a WTI phase. By tracking the temperature evolution of the (100) surface states, we unveil a thermal hysteresis of the surface gap in line with the {\alpha}-{\beta} structural phase transition. Our findings elucidate the topological properties of Bi4I4 and directly evidence a temperature-induced topological phase transition from WTI to HOTI, which paves the way to potential applications based on the room-temperature topological phase transition in the quasi-1D topological quantum material.
ISSN:2331-8422
DOI:10.48550/arxiv.2407.19375