Observation of a structurally driven, reversible topological phase transition in a distorted square net material
Abstract
Topological materials hold immense promise for exhibiting exotic quantum phenomena, yet achieving controllable topological phase transitions remains challenging. Here, we demonstrate a structurally driven, reversible topological phase transition in the distorted square net material GdPS, induced via in situ potassium dosing. Using angle-resolved photoemission spectroscopy and first principles calculations, we demonstrate a cascade of topological phases in the sub-surface P layer: from a large, topologically trivial band gap to a gapless Dirac cone state with a 2 eV dispersion, and finally to a two-dimensional topological insulator as inferred from theory. This evolution is driven by subtle structural distortions in the first P layer caused by potassium adsorption, which in turn contribute to the band gap closure and topological phase transition. Furthermore, the ability to manipulate the topology of a sub-surface layer in GdPS offers a unique route for exploring and controlling topological states in bulk materials.
Cite
@article{arxiv.2602.03937,
title = {Observation of a structurally driven, reversible topological phase transition in a distorted square net material},
author = {Xian P. Yang and Chia-Hsiu Hsu and Gokul Acharya and Junyi Zhang and Md Shafayat Hossain and Tyler A. Cochran and Bimal Neupane and Zi-Jia Cheng and Santosh Karki Chhetri and Byunghoon Kim and Shiyuan Gao and Yu-Xiao Jiang and Maksim Litskevich and Jian Wang and Yuanxi Wang and Jin Hu and M. Zahid Hasan},
journal= {arXiv preprint arXiv:2602.03937},
year = {2026}
}
Comments
Accepted by PRL