Nonlinear electromagnetic response and Higgs mode excitation in BCS superconductors with impurities

Abstract

We reveal that due to the presence of disorder oscillations of the order parameter amplitude called the Higgs mode can be effectively excited by the external electromagnetic radiation in usual BCS superconductors. This mechanism works for superconductors with both isotropic s-wave and anisotropic, such as d-wave, pairings. The non-linear response in the presence of impurities is captured by the quasiclassical formalism. We demonstrate that analytical solutions of the Eilenberger equation with impurity collision integral and external field drive coincide with the exact summation of ladder impurity diagrams. Using the developed formalism we show that resonant third-harmonic signal observed in recent experiments is naturally explained by the excitation of Higgs mode mediated by impurity scattering.

new references added, typos corrected

References in corpus (5)

• Amplitude / Higgs Modes in Condensed Matter Physics
• Synchronization in the BCS Pairing Dynamics as a Critical Phenomenon
• Amplitude Higgs mode and admittance in superconductors with a moving condensate
• Quasiclassical Theory on Third-Harmonic Generation in Conventional Superconductors with Paramagnetic Impurities
• Theory of nonequilibrium dynamics of multiband superconductors

Cited by in corpus (2)

• Nonlinear optical response of collective modes in multiband superconductors assisted by nonmagnetic impurities
• Signatures of Bardasis-Schrieffer mode excitation in Third-Harmonic generated currents