Transport features of topological corner states in honeycomb lattice with multihollow structure

TL;DR

This paper investigates the transport properties of topological corner states in a honeycomb lattice with multihollow structures, revealing resonant tunneling and enabling the construction of a single-electron source.

Contribution

It introduces a method to engineer multiple corner states in honeycomb lattices and studies their transport features, advancing the understanding of higher-order topological phases.

Findings

Existence of global resonant states in bulk insulator

Resonant tunneling of multiple corner states observed

Potential for single-electron source development

Abstract

Higher-order topological phase in 2-dimensional (2D) systems is characterized by in-gap corner states, which are hard to detect and utilize. We numerically investigate transport properties of topological corner states in 2D honeycomb lattice, where the second-order topological phase is induced by an in-plane Zeeman field in the conventional Kane-Mele model. Through engineering multihollow structures with appropriate boundaries in honeycomb lattice, multiple corner states emerge, which greatly increases the probability to observe them. A typical two-probe setup is built to study the transport features of a diamond-shaped system with multihollow structures. Numerical results reveal the existence of global resonant states in bulk insulator, which corresponds to the resonant tunneling of multiple corner states and occupies the entire scattering region. Furthermore, based on the well separated energy levels of multiple corner states, a single-electron source is constructed.