Oscillatory crossover from two dimensional to three dimensional topological insulators

TL;DR

This paper explores how reducing the thickness of 3D topological insulators like Bi2Te3 and Bi2Se3 causes an oscillatory transition to 2D topological insulators with quantum spin Hall effect, revealing a layered topological phase crossover.

Contribution

It introduces an analytical and computational study of the oscillatory crossover from 3D to 2D topological insulators as a function of layer thickness.

Findings

Crossover occurs in an oscillatory manner with layer thickness.

Alternates between topologically trivial and non-trivial phases.

Uses both analytical models and first-principles calculations.

Abstract

We investigate the crossover regime from three dimensional topological insulators $Bi_2Te_3$ and $Bi_2Se_3$ to two dimensional topological insulators with quantum spin Hall effect when the layer thickness is reduced. Using both analytical models and first-principles calculations, we find that the crossover occurs in an oscillatory fashion as a function of the layer thickness, alternating between topologically trivial and non-trivial two dimensional behavior.