Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Max Planck Institute of Microstructure Physics, Halle 06120, Germany.
Nano Lett. 2023 Apr 12;23(7):2476-2482. doi: 10.1021/acs.nanolett.2c03794. Epub 2023 Mar 27.
Step edges of topological crystalline insulators can be viewed as predecessors of higher-order topology, as they embody one-dimensional edge channels embedded in an effective three-dimensional electronic vacuum emanating from the topological crystalline insulator. Using scanning tunneling microscopy and spectroscopy, we investigate the behavior of such edge channels in PbSnSe under doping. Once the energy position of the step edge is brought close to the Fermi level, we observe the opening of a correlation gap. The experimental results are rationalized in terms of interaction effects which are enhanced since the electronic density is collapsed to a one-dimensional channel. This constitutes a unique system to study how topology and many-body electronic effects intertwine, which we model theoretically through a Hartree-Fock analysis.
拓扑晶体绝缘体的阶梯边缘可以被视为高阶拓扑的先驱，因为它们体现了从拓扑晶体绝缘体中涌现的有效三维电子真空中的一维边缘通道。我们使用扫描隧道显微镜和光谱学研究了 PbSnSe 中这种边缘通道在掺杂下的行为。一旦阶梯边缘的能量位置接近费米能级，我们就观察到关联能隙的打开。实验结果可以用增强的相互作用效应来合理化，因为电子密度坍塌到一维通道中。这构成了一个独特的系统来研究拓扑和多体电子效应如何交织在一起，我们通过哈特ree-fock 分析进行了理论建模。
