Probing superconductivity and pairing symmetry by coherent phonons in multiorbital superconductors

TL;DR

This paper proposes using phase information from coherent phonon oscillations as an experimental method to investigate superconductivity and pairing symmetries in multiorbital superconductors, revealing distinct behaviors for different pairing states.

Contribution

It introduces a novel approach to probe superconducting order parameters and pairing symmetries through phase analysis of coherent phonons in multiorbital superconductors.

Findings

Phase difference correlates with the superconducting order parameter.

Different pairing symmetries produce distinct phase behaviors.

Orbital-dependent sign change states cause discontinuous phase jumps.

Abstract

We show that the phase information contained in coherent phonon oscillations generated by a laser pulse in a multi- orbital superconductor can be used as an experimental tool to probe super- conductivity and pairing symmetries. The phase difference between the normal and superconducting states is proportional to the superconducting order parameter just below the superconducting transition temperature, Tc. It also exhibits different behaviors for superconducting states with different pairing symmetries. In particular, if there is an orbital-dependent internal sign change state, the phase difference can have a discontinuous jump below Tc.