Spiral Edge States in Topological 2D Sb2Te3 Crystals

Abstract

This work explores the edge state conduction properties of twinned and spiraled, 2D Sb2Te3 topological insulator crystals. We show the structure supports spatially continuous edge states within two spiral and knotted edge conduction channels. The channels are connected through a topological defect. This geometry introduces boundary conditions into the 2D crystal that modifies the edge state dispersion. Using a combination of low loss Electron Energy Loss Spectroscopy, Magnetic Force Microscopy and traditional carrier transport measurements we identify a distinct excitation at 0.155 eV in the spiral that seems to be related to two isolated states within the gap. This state is localized to the crystal edges. The modification of edge state bands using manipulation of a systems quantum geometry may open new avenues for the use of 2D topological systems.