Experimental Realization of the Topologically Nontrivial Phase in Monolayer Si₂Te₂

2025/08/10 by Huang, Xiaochun, Zhao, Lingxiao, Xiong, Rui +4
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)

paper · doi:10.48550/arxiv.2508.07351

Abstract

The free-standing monolayer Si₂Te₂ (ML-Si₂Te₂) 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 HfTe₂ serves as an ideal substrate for the epitaxial growth of ML-Si₂Te₂, preserving its topological phase. Scanning tunneling microscopy and spectroscopy confirm a strain-free (1 × 1) lattice of ML-Si₂Te₂, 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-Si₂Te₂ step edges, underscoring its topological nature.

Citations

• Ab‐initiosimulations of materials using VASP: Density‐functional theory and beyond
• Canonical dynamics: Equilibrium phase-space distributions

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