Statistical fluctuations of pumping and rectification currents in quantum dots

TL;DR

This paper studies the statistical fluctuations of pumping and rectification currents in chaotic quantum dots, highlighting the effects of temperature, dephasing, and magnetic fields through simulations and semiclassical analysis.

Contribution

It provides a detailed analysis of current fluctuations in quantum dots considering finite temperature, dephasing, and magnetic fields, extending previous models with numerical and semiclassical methods.

Findings

Thermal smearing suppresses current amplitude more than dephasing at intermediate temperatures.

Current fluctuations depend on the number of propagating channels and symmetry breaking.

Magnetic fields influence the statistics of rectified currents in quantum dots.

Abstract

We investigate the statistical fluctuations of currents in chaotic quantum dots induced by pumping and rectification at finite temperature and in the presence of dephasing. In open quantum dots, dc currents can be generated by the action of two equal-frequency ac gate voltages. The adiabatic regime occurs when the driving frequency is smaller than the electron inverse dwell time. Using numerical simulations complemented by semiclassical calculations, we consider both limits of small and large number of propagating channels in the leads when time-reversal symmetry is fully broken. We find that at intermediate temperature regimes, namely, $k_BT \alt \Delta$, where $\Delta$ is the mean single-particle level spacing, thermal smearing suppresses the current amplitude more effectively than dephasing. Motivated by recent theoretical and experimental works, we also study the statistics of rectified currents in the presence of a parallel, Zeeman splitting, magnetic field.