Optical signatures of shear collective modes in strongly interacting Fermi liquids

Abstract

The concept of Fermi liquid lays a solid cornerstone to the understanding of electronic correlations in quantum matter. This ordered many-body state rigorously organizes electrons at zero temperature in progressively higher momentum states, up to the Fermi surface. As such, it displays rigidity against perturbations. Such rigidity generates Fermi-surface resonances which manifest as longitudinal and transverse collective modes. Although these Fermi-liquid collective modes have been analyzed and observed in electrically neutral liquid helium, they remain unexplored in charged solid-state systems up to date. In this paper I analyze the transverse shear response of charged three-dimensional Fermi liquids as a function of temperature, excitation frequency and momentum, for interactions expressed in terms of the first symmetric Landau parameter. I consider the effect of momentum-conserving quasiparticle collisions and momentum-relaxing scattering in relaxation-time approximation on the coupling between photons and Fermi-surface collective modes, thus deriving the Fermi-liquid optical conductivity and dielectric function. In the high-frequency, long-wavelength excitation regime the electrodynamic response entails two coherent and frequency-degenerate polaritons, and its spatial nonlocality is encoded by a frequency- and interaction-dependent generalized shear modulus; in the opposite high-momentum low-frequency regime anomalous skin effect takes place. I identify observable signatures of propagating shear collective modes in optical spectroscopy experiments, with applications to the surface impedance and the optical transmission of thin films.

49 pages, 21 figures

References in corpus (9)

• The properties of ultrapure delafossite metals
• Non-Drude universal scaling laws for the optical response of local Fermi liquids
• Transport properties of strongly coupled electron-phonon liquids
• Electromagnetic properties of viscous charged fluids
• Electron hydrodynamics with a polygonal Fermi surface
• Propagation of shear stress in strongly interacting metallic Fermi liquids enhances transmission of terahertz radiation
• The universal shear conductivity of Fermi liquids and spinon Fermi surface states and its detection via spin qubit noise magnetometry
• Hydrodynamics of Fermi arcs: Bulk flow and surface collective modes
• Quantum Paracrystalline Shear Modes of the Electron Liquid

Cited by in corpus (12)

• Propagation of shear stress in strongly interacting metallic Fermi liquids enhances transmission of terahertz radiation
• Skin effect as a probe of transport regimes in Weyl semimetals
• The universal shear conductivity of Fermi liquids and spinon Fermi surface states and its detection via spin qubit noise magnetometry
• Collinear scattering and long-lived excitations in two-dimensional electron fluids
• Nonlocal conductivity, continued fractions and current vortices in electron fluids
• Soft modes in Fermi liquids at arbitrary temperatures
• Linear-in-temperature conductance in two-dimensional electron fluids
• Two-dimensional electron gases as non-Newtonian fluids
• Shear Bernstein modes in a two-dimensional electron liquid
• Acoustic plasmons and isotropic short-range interaction in two-component electron liquids
• Possible zero sound in layered perovskites with ferromagnetic $s$-$d$ exchange interaction
• Tomographic collective modes in a magnetic field