Effect of the type I to type II Weyl semimetal topological transition on superconductivity

TL;DR

This paper investigates how the topological transition between type I and type II Weyl semimetals affects superconductivity, revealing distinct spectral features and a spike in critical temperature at the transition point, with implications for experimental detection.

Contribution

It derives and solves Gorkov equations for superconductivity across the topological transition, highlighting spectral and critical temperature changes as novel indicators.

Findings

Critical temperature exhibits a spike at the transition point.

Spectral density differs markedly between phases, with characteristic band structures.

Superconductivity can serve as an indicator of topological phase transition.

Abstract

The influence of recently discovered topological transition between type I and type II Weyl semi-metals on superconductivity is considered. A set of Gorkov equations for weak superconductivity in Weyl semi-metal under topological phase transition is derived and solved. The critical temperature and superconducting gap both have spike in the point the transition point as function of the tilt parameter of the Dirac cone determined in turn by the material parameters like pressure. The spectrum of superconducting excitations is different in two phases: the sharp cone pinnacle is characteristic for a type I, while two parallel almost flat bands, are formed in type II. Spectral density is calculated on both sides of transition demonstrate different weight of the bands. The superconductivity thus can be used as a clear indicator for the topological transformation. Results are discussed in the light of recent experiments.