Experimental Realization of the Topologically Nontrivial Phase in Monolayer Si$_2$Te$_2$

Xiaochun Huang; Lingxiao Zhao; Rui Xiong; Wenbin Li; Bao-tian Wang; Baisheng Sa; Matthias Bode

paper

Experimental Realization of the Topologically Nontrivial Phase in Monolayer Si $_{2}$ Te $_{2}$

arXiv:2508.07351

Abstract

The free-standing monolayer Si $_{2}$ Te $_{2}$ (ML-Si $_{2}$ Te $_{2}$ ) has been theoretically predicted to host a room-temperature quantum spin Hall phase. However, its experimental realization remains challenge due to the absence of a three-dimensional counterpart. Here, we demonstrate that HfTe $_{2}$ serves as an ideal substrate for the epitaxial growth of ML-Si $_{2}$ Te $_{2}$ , preserving its topological phase. Scanning tunneling microscopy and spectroscopy confirm a strain-free $(1 \times 1)$ lattice of ML-Si $_{2}$ Te $_{2}$ , along with a sizable band gap, which is well captured by first-principles calculations. Moreover, distinct edge states, independent of step geometry and exhibiting a broad spatial distribution, are observed at ML-Si $_{2}$ Te $_{2}$ step edges, underscoring its topological nature.

6 pages, 5 figures

Experimental Realization of the Topologically Nontrivial Phase in Monolayer Si2​Te2​

Abstract

Experimental Realization of the Topologically Nontrivial Phase in Monolayer Si $_{2}$ Te $_{2}$