Surface states and local spin susceptibility in doped three-dimensional topological insulators with odd-parity superconducting pairing symmetry

TL;DR

This paper explores how Majorana surface modes in doped 3D topological insulators with odd-parity superconductivity influence local spin susceptibility, revealing distinctive temperature-dependent signatures detectable via depth-sensitive magnetic resonance techniques.

Contribution

It provides a theoretical analysis of the spin response associated with Majorana modes in topological insulators with odd-parity pairing, highlighting their experimental detectability.

Findings

Majorana modes affect local spin susceptibility and Knight shift.

Distinct decay lengths allow differentiation from Dirac modes.

Predicted temperature behavior in magnetic resonance experiments.

Abstract

We investigate characteristic features in the spin response of doped three-dimensional topological insulators with odd-parity unequal-spin superconducting pairing, which are predicted to have gapless Majorana surface modes. These Majorana modes contribute to the local spin susceptibility, giving rise to a characteristic temperature behavior of the Knight shift and the spin-lattice relaxation time in magnetic resonance experiments. Because of their different decay lengths, the Majorana modes can be observed and clearly distinguished from the Dirac modes of the topological insulator by local probes which allow for a depth-controlled study of the electron spins on the nanometer length scale.