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TT: Fachverband Tiefe Temperaturen
TT 55: Topology and Symmetry Protected Materials (joint session O/TT)
TT 55.7: Talk
Wednesday, March 20, 2024, 16:30–16:45, HL 001
The Trimer Chain: Robust Chiral Edge Mode in Artificial Electronic Lattices — •Rian Ligthart1, Amber Visser1, Dario Bercioux2, and Ingmar Swart1 — 1Debye Institute for Nanomaterials Science, Utrecht University, the Netherlands — 2Donostia International Physics Center, 20018 Donostia-San Sebastian, Spain
Artificial electronic lattices are a promising tool to study topology on an atomic scale. The Scanning Tunnelling Microscope (STM) allows to build the topological lattices by manipulating single atoms with nanoscale precision and to probe their electronic properties. Here, the semiconductor InAs(111)A surface with adsorbed Cs atoms is studied. Vertical and lateral manipulation allow to place multiple Cs-adatoms in vicinity of each other. Lines of positively charged Cs atoms create a potential well that confines the surface state electrons of InAs due to local band bending. The confined state acts as an artificial atom and can be used to construct a variety of structures. [1]
Artificial atoms can therefore be used as a platform to study the topological properties of model systems such as the SSH [2] and trimer chain. The trimer chain is similar to the SSH chain but has an extra atom in its unit cell. The extra hopping term introduces an extra degree of freedom in the system allowing to separate the the edge modes on the left and right side of the chain in energy. The trimer chain can therefore host a robust chiral edge mode on one side of the chain.
[1] E. Sierda, et al. Science 380, 1048-1052(2023)
[2] Van Dong Pham, et al. Phys. Rev. B, 105, 125418
Keywords: Scanning Tunneling Microscopy; Artificial Electronic Lattices; Trimer chain; SSH model; Robust Edge Modes