Electron Tunneling Spectroscopy of the Anisotropic Kitaev Quantum Spin Liquid Sandwiched with Superconductors

TL;DR

This paper investigates electron tunneling and spectroscopic features of a superconducting Josephson junction with an anisotropic Kitaev quantum spin liquid barrier, revealing unique spin correlations, topological phases, and Majorana fermion signatures.

Contribution

It provides the first detailed tunneling spectroscopy analysis of an anisotropic Kitaev QSL in a Josephson junction, linking spin dynamics to measurable electronic conductance.

Findings

Identification of spin gap and Majorana bands in conductance spectra

Observation of topological quantum phase transitions via tunneling spectroscopy

Detection of residual Kitaev QSL features in Josephson current

Abstract

We present the electron tunneling transport and spectroscopic characters of a superconducting {\it Josephson} junction with a barrier of single anisotropic Kitaev quantum spin liquid (QSL) layer. We find that the dynamical spin correlation features are well reflected in the direct-current differential conductance $dI^{c}/dV$ of the single-particle tunneling, including the unique spin gap and dressed itinerant Majorana dispersive band, in addition to an energy shift $2\Delta$ of two-lead superconducting gaps. From the spectral characters, we identify different topological quantum phases of the anisotropic Kitaev QSL. We also present the zero-voltage {\it Josephson} current $I^{s}$ which displays residual features of the anisotropic Kitaev QSL. These results pave a new way to measure the dynamical spinon or Majorana fermion spectroscopy of the Kitaev and other spin liquid materials.