Electron Tunneling Transport and Magnetic Field Modulation through a Superconductor-Kitaev layer-Superconductor Junction

TL;DR

This paper investigates electron tunneling and magnetic field effects in a superconductor-Kitaev layer-superconductor junction, revealing resonant peaks and magnetic suppression of the Josephson current, offering insights into spinon and Majorana fermion states.

Contribution

It introduces a novel analysis of tunneling transport in a superconductor-Kitaev layer junction and demonstrates magnetic field modulation effects on the Josephson current.

Findings

Resonant peaks at specific ratios of K/Δ due to spinon bands.

Magnetic field suppresses Josephson current by polarizing the Kitaev layer.

Critical magnetic field causes abrupt drop in tunneling current.

Abstract

We present the electron tunneling transport and its magnetic field modulation of a superconducting (SC) Josephson junction with a barrier of single ferromagnetic (FM) Kitaev layer. We find that at H = 0, the Josephson current IS displays two peaks at K/{\Delta} = 3.4 and 10, which stem from the resonant tunnelings between the SC gap boundaries and the spinon flat bands and between the SC gap edges and the spinon dispersive bands, respectively. With the increasing magnetic field, IS gradually decreases and abruptly drops to a platform at the critical magnetic field hc = g{\mu}BHc/{\Delta} = 0.03K/{\Delta}, since the applied field suppresses the spinon density of states (DOS) once upon the Kitaev layer enters the polarized FM phase. These results pave a new way to measure the spinon or Majorana fermion DOS of the Kitaev and other spin liquid materials.