Surface state reconstruction in ion-damaged SmB_6

TL;DR

This study investigates how ion-irradiation affects the surface states of SmB_6, revealing that the topologically protected surface state persists despite surface damage, through resistivity measurements and a reconstruction model.

Contribution

It demonstrates that ion-irradiation damages do not destroy the topological surface state but lead to its reconstruction beneath the damaged layer.

Findings

Residual resistivity decreases with damage depth

Surface state remains intact despite surface damage

Data supports topologically protected surface state model

Abstract

We have used ion-irradiation to damage the (001) surfaces of SmB_6 single crystals to varying depths, and have measured the resistivity as a function of temperature for each depth of damage. We observe a reduction in the residual resistivity with increasing depth of damage. Our data are consistent with a model in which the surface state is not destroyed by the ion-irradiation, but instead the damaged layer is poorly conducting and the initial surface state is reconstructed below the damage. This behavior is consistent with a surface state that is topologically protected.