Thermal resistivity and hydrodynamics of the degenerate electron fluid in antimony

Abstract

Detecting hydrodynamic fingerprints in the flow of electrons in solids constitutes a dynamic field of investigation in contemporary condensed matter physics. Most attention has been focused on the regime near the degeneracy temperature when the thermal velocity can present a spatially modulated profile. Here, we report on the observation of a hydrodynamic feature in the flow of quasi-ballistic degenerate electrons in bulk antimony. By scrutinizing the temperature dependence of thermal and electric resistivities, we detect a size-dependent departure from the Wiedemann-Franz law, unexpected in the momentum-relaxing picture of transport. This observation finds a natural explanation in the hydrodynamic picture, where upon warming, momentum-conserving collisions reduce quadratically in temperature both viscosity and thermal diffusivity. This effect has been established theoretically and experimentally in normal-state liquid 3He. The comparison of electrons in antimony and fermions in 3He paves the way to a quantification of momentum-conserving fermion-fermion collision rate in different Fermi liquids.

Boundary conductance in macroscopic bismuth crystals

“…The Dingle scattering time τ D , extracted from quantum oscillations is almost fifty times shorter than the transport scattering rate τ t r in Bi 42 . Such a large difference between τ t r and τ D has been observed in several other dilute metals 35 , 43 , 44 . The semiclassical high-field limit ( ω c τ t r ≈ 1) is satisfied when the cyclotron radius becomes shorter than the mean free path.…”

“…Note that the average mobility deduced from residual resistivity ignores the fact that in presence of anisotropic Fermi pockets of electrons and holes, the electrons and holes in different pockets and along different orientations have different mobilities. It is safe to assume that some carriers are ballistic given the size dependence of the residual resistivity 35 .…”

Boundary conductance protected by topology in macroscopic bismuth crystals

“…The Dingle scattering time τ D , extracted from quantum oscillations is almost fifty times shorter than the transport scattering rate τ tr in Bi [31]. Such a large difference between τ tr and τ D has been observed in several other dilute metals [26,33,34]. The semiclassical high-field limit (ω c τ tr ≈ 1) is satisfied when the cyclotron radius becomes shorter than the mean-freepath.…”

“…Note that the average mobility deduced from residual resistivity ignores the fact that in presence of anisotropic Fermi pockets of electrons and holes, the electrons and holes in different pockets and along different orientations have different mobilities. It is safe to assume that some carriers are ballistic given the size dependence of the residual resistivity [26].…”

Anti-Poiseuille flow in neutral graphene

“…The possibility for an electronic system to exhibit the Poiseuille flow in a narrow wire was first pointed out by Gurzhi [19][20][21]. Recently, similar behavior has been a subject of intense theoretical [22][23][24][25][26][27][28][29][30][31][32][33] and experimental [10][11][12][13]22,[34][35][36][37][38][39][40][41][42][43][44] research in the context of electronic transport in high-mobility 2D materials. In contrast to conventional fluids, the electronic flow is affected not only by viscous effects, but also by weak disorder scattering and is characterized by a typical length scale known as the Gurzhi length [26][27][28][29]33]…”