Formation of a Three-Component Electron-Hole-Phonon Fluid in Antimony
January 17th, 2020 ALEXANDRE JAOUI College de France

The ballistic/diffusive picture of transport adequately describes the flow of quasiparticles in the vast majority of solids. Momentum-conserving collisions, which set the viscosity of the fluid, are neglected in this picture. Nevertheless, theory expects hydrodynamic features for both electrons and phonons at the passage between the diffusive and the ballistic regimes. Viscous electrons have been reported in a couple of mesoscopic ultra-pure metals. Phonon hydrodynamics were observed in a handful of bulk insulators.

Here, we show that hydrodynamic corrections to both the electronic and phononic transport properties are visible at the onset of the ballistic regime in macroscopic Sb crystals. Specifically, we find a size-dependent violation of the Wiedemann-Franz law for electrons flow and a non-monotonous temperature dependence of the phonon thermal diffusivity. The simultaneous electron-phonon hydrodynamics arise because momentumconserving collisions between phonons and carriers of both signs outweigh all other scattering events.

Seminar, January 17, 2020, 12:00. ICFO’s Seminar Room

Hosted by Prof. Dmitri Efetov