Tunneling Density of States, Pair Correlation, and Josephson Current in Spin-Incoherent Luttinger Liquid-Superconductor Hybrid Systems

TL;DR

This paper investigates the electronic properties of a hybrid system combining a spin-incoherent Luttinger liquid with superconductors, revealing universal low-energy behavior and robust Josephson current despite exponential decay of pair correlations.

Contribution

It demonstrates universal tunneling density of states and the persistence of Josephson current in spin-incoherent Luttinger liquids, highlighting differences from zero-temperature Luttinger liquids.

Findings

Tunneling density of states diverges at low energies with universal frequency dependence.

Josephson current remains robust despite exponential decay of pair correlations.

Critical current is reduced by a factor of 2, and phase period is halved compared to zero-temperature Luttinger liquids.

Abstract

We study a hybrid system consisting of a spin-incoherent Luttinger liquid adjoined at one or both ends to a superconductor. We find the tunneling density of states diverges at low energies and exhibits a universal frequency dependence independent of the strength of the interactions in the system. We show that in spite of exponentially decaying pair correlations with distance into the spin-incoherent Luttinger liquid, the Josephson current remains robust. Compared to the zero temperature Luttinger liquid case there is a factor of 2 reduction in the critical current and a halving of the period in the phase difference between the superconductors. Our results open the way for a new class of experiments in the spin-incoherent regime of one dimensional systems.