Measuring intrinsic relaxation rates in superconductors using nonlinear response

Abstract

We discuss intrinsic relaxation rates in superconductors, and how they may be measured using non-linear optical (terahertz) response. We consider both $s$ and $d$-wave superconductors, both with and without a phenomenological (energy dependent) damping. Intrinsic relaxation rates of interest include the Higgs mode decay rate, the quasiparticle redistribution rate ($1/T_1$) and the quasiparticle dephasing rate ($1/T_2$), where the latter two rates are zero in the pure BCS model, but non-zero in the presence of damping. Using the Anderson pseudospin formalism, we illustrate how these intrinsic relaxation rates are related to measurable quantities such as the time-dependent gap function and the non-linear current (a.k.a. third harmonic generation). Hence, we show how intrinsic relaxation rates may be experimentally extracted and discuss what one may thereby learn about the underlying damping. We also discuss the effects of polarization control (viz. non-linear response to light polarized in different directions), which offers a useful experimental knob, especially for $d$-wave superconductors, enabling selective excitation of modes in different irreducible representations (and readout of their corresponding relaxation rates).

References in corpus (30)

• Higgs Amplitude Mode in BCS Superconductors Nb${}_{1-x}$Ti${}_x$N induced by Terahertz Pulse Excitation
• Higgs Mode in Superconductors
• Tracking Cooper Pairs in a Cuprate Superconductor by Ultrafast Angle-Resolved Photoemission
• Theory of Anderson pseudospin resonance with Higgs mode in superconductors
• Dynamical vanishing of the order parameter in a fermionic condensate
• Non-linear optical effects and third-harmonic generation in superconductors: Cooper-pairs vs Higgs mode contribution
• Higgs mode in the d-wave superconductor Bi2Sr2CaCu2O8+x driven by an intense terahertz pulse
• Momentum-Resolved Ultrafast Electron Dynamics in Superconducting Bi2Sr2CaCu2O8+delta
• Quantum quench in a p + i p superfluid: Winding numbers and topological states far from equilibrium
• Resolving continua of fractional excitations by spinon echo in THz 2D coherent spectroscopy
• Nonlinear electromagnetic response and Higgs mode excitation in BCS superconductors with impurities
• Nonequilibrium dynamics of weakly and strongly paired superconductors
• Classification and characterization of nonequilibrium Higgs modes in unconventional superconductors
• Transient Dynamics of d-wave Superconductors after a Sudden Excitation
• Nonlinear optical response of collective modes in multiband superconductors assisted by nonmagnetic impurities
• Third harmonic generation from collective modes in disordered superconductors
• Twisting Anderson pseudospins with light: Quench dynamics in THz-pumped BCS superconductors
• Theory of coherent oscillations detection in THz pump-probe spectroscopy: from phonons to electronic collective modes
• Higgs-mediated optical amplification in a non-equilibrium superconductor
• Spectroscopic fingerprints of gapped quantum spin liquids, both conventional and fractonic
• Higgs-mode resonance in third harmonic generation in NbN superconductors: multiband electron-phonon coupling, impurity scattering, and polarization-angle dependence
• Revealing novel aspects of light-matter coupling in terahertz two-dimensional coherent spectroscopy: the case of the amplitude mode in superconductors
• Extracting spinon self-energies from two-dimensional coherent spectroscopy
• Impact of damping on superconducting gap oscillations induced by intense Terahertz pulses
• Higgs Oscillations in time-resolved Optical Conductivity
• Signatures of fractional statistics in nonlinear pump-probe spectroscopy
• Quench-drive spectroscopy and high-harmonic generation in BCS superconductors
• Post-quench gap dynamics of two-band superconductors
• Momentum-resolved analysis of condensate dynamic and Higgs oscillations in quenched superconductors with tr-ARPES
• Collisionless dynamics in disordered superconductors