Superconducting Acoustogalvanic Effect in Twisted Transition Metal Dichalcogenides

TL;DR

This paper introduces a novel method using surface acoustic waves to probe the superconducting gap structure and exotic quasiparticles in two-dimensional van der Waals superconductors, aiding the identification of unconventional pairing symmetries.

Contribution

It proposes a nonlinear response technique driven by surface acoustic waves as a new tool to investigate the quantum geometry and pairing symmetries in 2D superconductors.

Findings

Surface acoustic waves can access Bogoliubov quasiparticles.

The method is suitable for low-$T_c$ superconductors.

Potential for experimental identification of exotic states.

Abstract

Two-dimensional van der Waals superconductors are attracting much attention owing to their rich phase diagrams including possible unconventional superconductivity. However, they suffer from a lack of reliable methods for identifying their nontrivial pairing symmetries and quantum geometry. In this study, we propose nonlinear responses driven by surface acoustic waves as a novel probe to access exotic Bogoliubov quasiparticles in such superconductors. Our approach is particularly suitable for addressing the superconducting gap structure as the gap energies in these systems typically lie within the frequency range of surface acoustic waves, and thus paves the way toward the experimental identification of exotic superconducting states especially in low-$T_c$ superconductors.