2017/04/07 by Martin Eckstein, Eckstein, Martin, Philipp Werner +1
Engineering · Physics and Astronomy · #FOS: Physical sciences #Molecular Junctions and Nanostructures #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.1704.02300
11 pages, 6 figures
arxiv created 2017/04/07 · openalex publication_date 2017/04/07 · arxiv updated 2017/04/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate a quantum dot (Anderson impurity) coupled to metallic leads, with a time-periodic voltage bias across the device. Using a time-dependent Schrieffer-Wolff transformation, we show that the Floquet Hamiltonian of the model can be mapped onto a two-channel Kondo model, in which the impurity is screened by separate conduction bands corresponding to parity-even and odd superpositions of the metallic leads. By changing the frequency and amplitude of the perturbation, one can tune the system to a quantum critical point with symmetric coupling of the impurity to both channels. For the understanding of the driven state, energy absorption from the drive must be considered: Although the absorption at the impurity is balanced by the energy flow into the conduction band, locally it leads to non-thermal distribution functions which can have a detrimental effect on the Kondo physics. However, a numerical simulation demonstrates that the absorption can be systematically suppressed at a fixed value of the induced couplings by increasing the frequency, so that the time-averaged dynamics in the driven one-channel Anderson model can be used to study the critical behavior of the two-channel model.