论文标题
二维拓扑绝缘子候选者的外延生长：单层SI2TE2
Epitaxial growth of a two-dimensional topological insulator candidate: monolayer Si2Te2
论文作者
论文摘要
六边形SI2TE2单层（ML-SI2TE2）被预测在半导体和室温量子旋转大厅相之间显示出应变依赖性的带状分裂。但是，对这种人工二维（2D）材料的研究主要仅限于理论计算，因为它的大量对应物不存在自然存在。在这里，我们报告了SB2TE3薄膜底物上ML-SI2TE2膜成功的外延生长。通过扫描隧道显微镜揭示的高质量（1*1）ML-SI2TE2膜的覆盖率高达95％。 X射线光电子光谱证实了界面处的SI2TE2和SB2TE3之间的混合。通过将扫描隧道光谱与密度功能理论计算相结合，我们证明了SB2TE3上ML-SI2TE2的半导体带结构。此外，从理论上讲，通过使用应变工程将应变减少4.4％，可以预测系统可以驱动到非平凡阶段。我们的结果为这位2D拓扑绝缘子候选者的深入研究铺平了道路。
Hexagonal Si2Te2 monolayers (ML-Si2Te2) were predicted to show strain-dependent band-crossover between semiconducting and room-temperature quantum spin Hall phases. However, investigations on this artificial two-dimensional (2D) material have mainly been restricted to theoretical calculations because its bulk counterpart does not exist naturally. Here, we report on the successful epitaxial growth of ML-Si2Te2 films on Sb2Te3 thin film substrates. High-quality (1*1) ML-Si2Te2 films with a coverage as high as 95% were obtained as revealed by scanning tunneling microscopy. X-ray photoelectron spectroscopy confirms the absence of intermixing between Si2Te2 and Sb2Te3 at the interface. By combining scanning tunneling spectroscopy with density functional theory calculations, we demonstrate the semiconducting band structure of ML-Si2Te2 on Sb2Te3. Furthermore, it is theoretically predicted that the system can be driven into the nontrivial phase via reducing the strain by 4.4% using strain engineering. Our results pave the way for in-depth investigations on this 2D topological insulator candidate.
