Phonon-Induced Zero-bias Currents in Solids

TL;DR

This paper investigates how propagating phonons induce zero-bias currents in metals and CDW systems on piezoelectric substrates, revealing symmetry-breaking effects and temperature-dependent behaviors with potential experimental implications.

Contribution

It provides a microscopic analysis of phonon-induced zero-bias currents, highlighting the role of inversion symmetry breaking and the influence of deformation and piezoelectric potentials.

Findings

Zero-bias current appears below the CDW transition temperature.

The current magnitude depends strongly on the chemical potential position.

Propagating phonons break inversion symmetry, enabling zero-bias currents.

Abstract

Zero-bias current induced by injected phonons in metals and one-dimensional charge density wave (CDW) systems attached on the surface of the piezoelectric substrate is investigated microscopically based on the second order response theory. In contrast to the shift currents discovered by von Baltz and Kraut in which the zero-bias current is induced by AC electric field in systems without inversion symmetry, propagating phonons break the inversion symmetry in the presesnt case. The effects of both deformation potential and piezoelectric potential are taken into account. In the CDW system, zero-bias current appears below the transition temperature and its magnitude strongly depends on the position of the chemical potential. Possible experimental consequences are discussed.