Magnetic field symmetry of pump currents of adiabatically driven mesoscopic structures

TL;DR

This paper analyzes the symmetry properties of pump currents in adiabatically driven mesoscopic structures, revealing that the Floquet scattering matrix contains additional information beyond the frozen matrix, affecting magnetic field symmetry and rectification.

Contribution

It demonstrates that the Floquet scattering matrix at low frequencies includes an irreducible part with distinct symmetry properties, advancing understanding of adiabatic quantum pumping.

Findings

Floquet matrix includes an additional matrix reflecting time dependence.

Symmetry properties of the Floquet matrix differ from the frozen matrix.

Quantum rectification in pumped systems shows specific magnetic and voltage symmetry behaviors.

Abstract

We examine the scattering properties of a slowly and periodically driven mesoscopic sample using the Floquet function approach. One might expect that at sufficiently low driving frequencies it is only the frozen scattering matrix which is important. The frozen scattering matrix reflects the properties of the sample at a given instant of time. Indeed many aspects of adiabatic scattering can be described in terms of the frozen scattering matrix. However, we demonstrate that the Floquet scattering matrix, to first order in the driving frequency, is determined by an additional matrix which reflects the fact that the scatterer is time-dependent. This low frequency irreducible part of the Floquet matrix has symmetry properties with respect to time and/or a magnetic field direction reversal opposite to that of the frozen scattering matrix. We investigate the quantum rectification properties of a pump which additionally is subject to an external dc voltage. We split the dc current flowing through the pump into several parts with well defined properties with respect to a magnetic field and/or an applied voltage inversion.