Probing topological phase transitions via quantum reflection in the graphene family materials

TL;DR

This paper demonstrates that quantum reflection probabilities of atoms near 2D materials like silicene, germanene, and stanene reveal topological phase transitions, and these effects can be tuned with external electric fields and light.

Contribution

It introduces a method to detect topological phase transitions in 2D materials through quantum reflection measurements, using Lifshitz theory for accurate potential calculations.

Findings

Quantum reflection probabilities show clear signatures of topological phase transitions.

External electric fields and circularly polarized light can tune quantum reflection by up to 40%.

Dispersive forces are key in atom-surface interactions related to topological phases.

Abstract

We theoretically investigate the quantum reflection of different atoms by two-dimensional (2D) materials of the graphene family (silicene, germanene, and stanene), subjected to an external electric field and circularly polarized light. By using Lifshitz theory to compute the Casimir-Polder potential, which ensures that our predictions apply to all regimes of atom-2D surface distances, we demonstrate that the quantum reflection probability exhibits distinctive, unambiguous signatures of topological phase transitions that occur in 2D materials. We also show that the quantum reflection probability can be highly tunable by these external agents, depending on the atom-surface combination, reaching a variation of 40% for Rubidium in the presence of a stanene sheet. Our findings attest that not only dispersive forces play a crucial role in quantum reflection, but also that the topological phase transitions of the graphene family materials can be comprehensively and efficiently probed via atom-surface interactions at the nanoscale.