van der Waals Heterostructures of Germanene, Stanene and Silicene with Hexagonal Boron Nitride and Their Topological Domain Walls

TL;DR

This paper explores van der Waals heterostructures combining germanene, stanene, or silicene with hexagonal boron nitride, demonstrating their topological properties and potential for engineered topological domain walls with protected edge states.

Contribution

It introduces the design and analysis of vdW heterostructures with tunable topological phases and domain walls, enabling control over edge states via patterning and external fields.

Findings

Topological phase transitions can be controlled by substrate effects and electric fields.

Valley polarized quantum spin Hall and valley-contrasting edge states are realized.

Heterostructure patterning enables tailored topological edge states.

Abstract

We investigate van der Waals (vdW) heterostructures made of germanene, stanene or silicene with hexagonal Boron Nitride (h-BN). The intriguing topological properties of these buckled honeycomb materials can be maintained and further engineered in the heterostructures, where the competition between the substrate effect and external electric fields can be used to control the tunable topological phase transitions. Using such heterostructures as building blocks, various vdW topological domain walls (DW) are designed, along which there exist valley polarized quantum spin Hall edge states or valley-contrasting edge states which are protected by valley(spin)- resolved topological charges and can be tailored by the patterning of the heterojunctions and by external fields.