2021/10/15 by Qiang Gao, Gao, Qiang, Yafei Ren +3 · 1 citation
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Other Condensed Matter (cond-mat.other) #Quantum and electron transport phenomena #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.48550/arxiv.2110.07863
openalex publication_date 2021/10/15 · openalex created_date 2022/07/19 · openalex updated_date 2026/07/28
We study the DC current generation in a periodically driven Bloch system connected to a heat bath. Under a relaxation time approximation, the density matrix for such a system is obtained, which is related to two equilibria: a Floquet quasi-equilibrium where the density matrix is diagonal under the Floquet-Bloch eigenbasis and an instantaneous Bloch thermal equilibrium. Then, the current responses and their power features, i.e. the power input behavior, are discussed in a unified manner, which reveals that there exist an intrinsic current and an extrinsic correction. Remarkably, the intrinsic part consumes no energy and corresponds to the Floquet quasi-equilibrium, while the extrinsic part needs a sustained energy input and originates from a shift between two equilibrium ensembles. We further investigate the role of the external driving field strength finding that large DC currents can be generated under a relatively strong but not too strong driving field.