Issue 19, 2022

Persistence of symmetry-protected Dirac points at the surface of the topological crystalline insulator SnTe upon impurity doping

Abstract

We investigate the effect of a non-magnetic donor impurity located at the surface of the SnTe topological crystalline insulator. In particular, the changes on the surface states due to a Sb impurity atom are analyzed by means of ab initio simulations of pristine and impurity-doped SnTe. Both semi-infinite and slab geometries are considered within the first-principles approach. Furthermore, minimal and Green's function continuum models are proposed with the same goal. We find that the Dirac cones are shifted down in energy upon doping; this shift strongly depends on the position of the impurity with respect to the surface. In addition, we observe that the width of the impurity band presents an even–odd behavior by varying the position of the impurity. This behavior is related to the position of the nodes of the wave function with respect to the surface, and hence it is a manifestation of confinement effects. We compare slab and semi-infinite geometries within the ab initio approach, demonstrating that the surface states remain gapless and their spin textures are unaltered in the doped semi-infinite system. In the slab geometry, a gap opens due to hybridization of the states localized at opposite surfaces. Finally, by means of a continuum model, we extrapolate our results to arbitrary positions of the impurity, clearly showing a non-monotonic behavior of the Dirac cone.

Graphical abstract: Persistence of symmetry-protected Dirac points at the surface of the topological crystalline insulator SnTe upon impurity doping

Associated articles

Article information

Article type
Paper
Submitted
27 Oct 2021
Accepted
21 Mar 2022
First published
05 Apr 2022
This article is Open Access
Creative Commons BY-NC license

Nanoscale, 2022,14, 7151-7162

Persistence of symmetry-protected Dirac points at the surface of the topological crystalline insulator SnTe upon impurity doping

O. Arroyo-Gascón, Y. Baba, J. I. Cerdá, O. de Abril, R. Martínez, F. Domínguez-Adame and L. Chico, Nanoscale, 2022, 14, 7151 DOI: 10.1039/D1NR07120C

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements