Quantum strain sensor with a topological insulator HgTe quantum dot

TL;DR

This paper proposes a quantum strain sensor based on HgTe quantum dots that utilize a strain-induced topological phase transition, significantly affecting conductivity and enabling sensitive detection.

Contribution

It introduces a theoretical model of HgTe quantum dots as strain sensors exploiting topological phase transitions and edge state control for enhanced sensing capabilities.

Findings

Strain induces a transition from topological to normal phase in HgTe quantum dots.

Edge states significantly influence the quantum dot's conductivity.

The model enables tunable sensor sensitivity via size and strain adjustments.

Abstract

We present a theory of electronic properties of HgTe quantum dot and propose a strain sensor based on a strain-driven transition from a HgTe quantum dot with inverted bandstructure and robust topologically protected quantum edge states to a normal state without edge states in the energy gap. The presence or absence of edge states leads to large on/off ratio of conductivity across the quantum dot, tunable by adjusting the number of conduction channels in the source-drain voltage window. The electronic properties of a HgTe quantum dot as a function of size and applied strain are described using eight-band kp Luttinger and Bir-Pikus Hamiltonians, with surface states identified with chirality of Luttinger spinors and obtained through extensive numerical diagonalization of the Hamiltonian.