Prediction of topological superconductivity in 1$T$-TiTe$_2$ under pressure

TL;DR

This paper predicts that 1$T$-TiTe$_2$ can become a topological superconductor under pressure, hosting Majorana modes, with potential advantages over doped systems, based on first-principles calculations and effective Hamiltonian analysis.

Contribution

It demonstrates that 1$T$-TiTe$_2$ is a topological metal capable of topological superconductivity without doping, and suggests transition metal intercalation as an alternative route.

Findings

1$T$-TiTe$_2$ hosts Dirac cone surface states near the Fermi level.

It exhibits a normal-topological-normal superconductivity phase transition with chemical potential.

Transition metal intercalation may realize topological superconductivity and Majorana zero modes.

Abstract

Topological superconductivity has attracted intensive interest for its ability of hosting Majorana zero mode and implementing in topological quantum computations. Based on the first-principles calculations and the analysis of the effective BdG Hamiltonian, we demonstrate that 1$T$-TiTe$_2$ is a topological metal hosting Dirac cone type of surface states near the Fermi level, and it exhibits a normal-topological-normal superconductivity phase transition as a function of the chemical potential. These results point out a new promising topological superconductor without random dopant, in which the influence of the impurity may be greatly reduced. Furthermore, our calculations also suggest that the transition metal intercalated Ti(Se$_{1-y}$Te$_y$)$_2$ is also a highly possible route to realize TSC and MZMs.