Theory of tunneling spectroscopy in the Larkin-Ovchinnikov state

TL;DR

This paper develops a theoretical framework for tunneling spectroscopy in the Larkin-Ovchinnikov state, revealing distinctive spectral features that differentiate it from other superconducting states and proposing an experimental identification method.

Contribution

It introduces a comprehensive theory accounting for the periodic pair potential modulation in the LO state, highlighting unique spectral signatures.

Findings

Tunneling spectra exhibit characteristic line shapes with multiple maxima and minima.

Spectral features reflect minigap structures due to periodic pair potentials.

Proposes an experimental method to identify the LO state based on spectral analysis.

Abstract

A theory of the tunneling spectroscopy of normal metal / Larkin-Ovchinnikov (LO) state is presented by fully taking account of the periodic modulation of pair potentials in real space. The resulting tunneling spectra have characteristic line shapes with several maxima and minima reflecting minigap structures due to the periodic pair potentials. These features are qualitatively different from tunneling spectra of Fulde-Ferrell state and those of uniform $s$- and d-wave superconductors. On the basis of calculated results, we propose a method to identify the LO state in actual experiments.