Density functional Bogoliubov-de Gennes calculations for a topological superconductor

The possibility to combine topological electronic band structures and superconductivity (SC) opens new pathways towards engineering exotic quantum matter. Proximity induced superconductivity in the topological surface state of topological insulators (TIs) offers the possibility to realize a chiral p-wave superconductor. Such a superconductor is an exotic state of matter which supports non-Abelian anyons and is of great interest for Majorana-based quantum computing applications [1]. Material-specific insights into the microscopic details of such superconductor/TI interfaces are of great interest and an indispensable ingredient in the challenging materials optimization problem.

Here we first introduce the recent Bogoliubov de-Gennes (BdG) extension to the all electron full potential relativistic Korringa-Kohn-Rostoker (KKR) Green function code JuKKR [2,3]. This KKR-BdG method allows a description of inhomogeneous superconductors on the basis of density functional theory. We apply this method to the s-wave superconductor Nb and study its 110 surface [2]. We then turn to the investigation of the proximity effect in Nb/TI interfaces and discuss the induced superconductivity in the topological surface state of this SC/TI heterostructure.

[1] Masatoshi Sato and Yoichi Ando 2017 Rep. Prog. Phys. 80 076501 

[2] Philipp Rüßmann and Stefan Blügel, Density functional Bogoliubov-de Gennes analysis of superconducting Nb and Nb(110) surfaces. arXiv:2110.01713 (2021)

[3] https://jukkr.fz-juelich.de