Born effective charges and vibrational spectra in super and bad conducting metals

Abstract

Interactions mediated by electron-phonon coupling are responsible for important cooperative phenomena in metals such as superconductivity and charge-density waves. The same interaction mechanisms produce strong collision rates in the normal phase of correlated metals, causing sizeable reductions of the dc conductivity and reflectivity. As a consequence, low-energy excitations like phonons, which are crucial for materials characterization, become visible in optical infrared spectra. A quantitative assessment of vibrational resonances requires the evaluation of dynamical Born effective charges, which quantify the coupling between macroscopic electric fields and lattice deformations. We show that the Born effective charges of metals crucially depend on the collision regime of conducting electrons. In particular, we describe, within a first principles framework, the impact of electron scattering on the infrared vibrational resonances, from the undamped, collisionless regime to the overdamped, collision-dominated limit. Our approach enables the interpretation of vibrational reflectance measurements of both super and bad conducting metals, as we illustrate for the case of strongly electron-phonon coupled superhydride H${}_3$S.

References in corpus (8)

• Universal dynamical conductance in graphite
• Electrodynamics of Correlated Electron Materials
• Pristine and intercalated transition metal dichalcogenide superconductors
• Giant non-adiabatic effects in layer metals: Raman spectra of intercalated graphite explained
• Charged-phonon theory and Fano effect in the optical spectroscopy of bilayer graphene
• Electron-phonon interaction and longitudinal-transverse phonon splitting in doped semiconductors
• Electron-phonon interaction and phonons in 2d doped semiconductors
• Spectroscopic signatures of phonons in high pressure superconducting hydrides

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• Beyond-quasiparticle transport with vertex correction: self-consistent ladder formalism for electron-phonon interactions
• Elastic Constants and Bending Rigidities from Long-Wavelength Perturbation Expansions