# Tuning topological surface states by cleavage angle in topological crystalline insulators

## TL;DR

This paper investigates how the topological surface states in crystalline insulators are affected by the angle of surface cleavage, using first-principles models to understand the impact of macroscopic imperfections.

## Contribution

It introduces a systematic theoretical approach to study the effects of cleavage angle deviations on topological surface states in crystalline insulators.

## Key findings

- Surface states are sensitive to cleavage angle variations.
- Theoretical framework applicable to various topological insulators.
- Insights into macroscopic imperfections' effects on surface states.

## Abstract

The conducting states, recently discovered at the surface of two special class of insulators -- topological insulators and topological crystalline insulators - are distinguished by their insensitivity to local and non-magnetic surface defects at a level of disorder, sufficiently small to be described within the perturbation theory. However, the behavior of the surface states in case of non local macroscopic imperfections is not clear. Here, we propose a systematic study of the topological surface states on vicinal planes (deviations from perfect surface cleavage) in a topological crystalline insulator of the tin telluride family, by using realistic first-principles-derived tight-binding models. The theoretical framework proposed is quite general and easily permits the extensions to other topological insulator families.