Numerical study of parametric pumping current in mesoscopic systems in the presence of magnetic field

TL;DR

This study numerically explores how magnetic fields influence parametric pumped currents in mesoscopic systems, revealing differences between adiabatic and non-adiabatic regimes, especially at resonances and anti-resonances, with implications for symmetry and current behavior.

Contribution

It provides new insights into the behavior of pumped currents under magnetic fields in both adiabatic and non-adiabatic regimes, including symmetry relations and effects of system parameters.

Findings

Adiabatic pumped current changes sign at sharp resonance; non-adiabatic does not.

At complete transmission energy, adiabatic current is zero, non-adiabatic is non-zero.

Both currents are zero at anti-resonance with complete reflection.

Abstract

We numerically study the parametric pumped current when magnetic field is applied both in the adiabatic and non-adiabatic regimes. In particular, we investigate the nature of pumped current for systems with resonance as well as anti-resonance. It is found that in the adiabatic regime, the pumped current changes sign across the sharp resonance with long lifetime while the non-adiabatic pumped current at finite frequency does not. When the lifetime of resonant level is short, the behaviors of adiabatic and non-adiabatic pumped current are similar with sign changes. Our results show that at the energy where complete transmission occurs the adiabatic pumped current is zero while non-adiabatic pumped current is non-zero. Different from the resonant case, both adiabatic and non-adiabatic pumped current are zero at anti-resonance with complete reflection. We also investigate the pumped current when the other system parameters such as magnetic field, pumped frequency, and pumping potentials. Interesting behaviors are revealed. Finally, we study the symmetry relation of pumped current for several systems with different spatial symmetry upon reversal of magnetic field. Different from the previous theoretical prediction, we find that a system with general inversion symmetry can pump out a finite current in the adiabatic regime. At small magnetic field, the pumped current has an approximate relation I(B) \approx I(-B) both in adiabatic and non-adiabatic regimes.