High-frequency flow of two-dimensional viscous electron fluid in magnetic field: transversal zero sound and manifestation of the viscous resonance

P. S. Alekseev, A. P. Alekseeva

Published 2018-10-24Version 1

Conductive electrons in high-quality two-dimensional (2D) materials at low temperatures can form a viscous fluid. We study a linear response of a 2D strongly-nonideal electron fluid in magnetic field on circularly polarized electric field. We demonstrate that the response consists of the two parts: the first one formed by the magnetoplasmons and the second one formed by the transversal zero sound. Such the sound exists in strongly non-ideal Fermi liquids and is similar to the transversal sound in amorphous solid media. In this paper we study such waves in a charged fluid in magnetic field on the example of a 2D strongly non-ideal electron fluid. The viscous part of the linear response is almost independent on the sign of circular polarization of ac field and exhibits the viscous resonance, which was recently proposed in the work [P. S. Alekseev, arXiv:1802.09179v3 (2017)]. The viscous resonance manifests itself also via the plasmonic part of the linear response by a resonant dependence of the width of the plasmonic resonance on magnetic field. We argue that, apparently, the viscous resonance is responsible for the peak and the features observed in photoresistance and photovoltage of the ultra-pure GaAs quantum wells. This fact should be considered as an evidence of forming a 2D viscous electron fluid in such the structures.