Spontaneous strain and magnetization in doped topological insulators with nematic and chiral superconductivity

TL;DR

This paper predicts that doped topological insulators with nematic or chiral superconductivity can exhibit spontaneous strain and magnetization, with transitions controllable by magnetic field and strain, affecting magnetic susceptibility and stiffness.

Contribution

It introduces the theoretical possibility of spontaneous strain and magnetization in doped topological insulators with two-component superconducting order parameters, depending on symmetry.

Findings

Spontaneous strain and magnetization can occur in doped topological insulators.

Transitions between nematic and chiral states can be controlled by magnetic field and strain.

Transitions involve jumps in magnetic susceptibility and mechanical stiffness.

Abstract

We show that a spontaneous strain and spontaneous magnetization can arise in the doped topological insulators with a two-component superconducting vector order parameter. The details of the effects crucially depend on the symmetry of the superconducting order parameter, whether it is nematic or chiral. The transition from the nematic state to the chiral one can be performed by application of a magnetic field while the transition from the chiral state to the nematic one is tuned by the external strain. These transitions associated with a jump of the magnetic susceptibility and mechanical stiffness. Possible experimental observations of the predicted effects are discussed.