Nonequilibrium steady-state thermoelectrics of Kondo-correlated quantum dots

Fuente: arXiv
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Autores principales: Manaparambil, Anand, Weichselbaum, Andreas, von Delft, Jan, Weymann, Ireneusz
Formato: Preprint
Publicado: 2024
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author Manaparambil, Anand
Weichselbaum, Andreas
von Delft, Jan
Weymann, Ireneusz
author_facet Manaparambil, Anand
Weichselbaum, Andreas
von Delft, Jan
Weymann, Ireneusz
contents The transport across a Kondo-correlated quantum dot coupled to two leads with independent temperatures and chemical potentials is studied using a controlled non-perturbative, and in this sense exact numeric treatment based on a hybrid numerical renormalization group combined with time-dependent density matrix renormalization group (NRG-tDMRG). We find a peak in the conductance at finite voltage bias vs. the temperature gradient $ΔT = T_R - T_L$ across left and right lead. We then focus predominantly on zero voltage bias but finite $ΔT$ far beyond linear response. We reveal the dependence of the characteristic zero-bias conductance on the individual lead temperatures. We find that the finite-$ΔT$ data behaves quantitatively similar to linear response with an effective equilibrium temperature derived from the different lead temperatures. The regime of sign changes in the Seebeck coefficient, signaling the presence of Kondo correlations, and its dependence on the individual lead temperatures provide a complete picture of the Kondo regime in the presence of finite temperature gradients. The results from the zero-bias conductance and Seebeck coefficient studies unveil an approximate `Kondo circle' in the $T_L/T_R$ plane as the regime within which the Kondo correlations dominate. We also study the heat current and the corresponding heat conductance vs. finite $ΔT$. We provide a polynomial fit for our numerical results for the thermocurrent as a function of the individual lead temperatures which may be used to fit experimental data in the Kondo regime.
format Preprint
id arxiv_https___arxiv_org_abs_2409_03102
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Nonequilibrium steady-state thermoelectrics of Kondo-correlated quantum dots
Manaparambil, Anand
Weichselbaum, Andreas
von Delft, Jan
Weymann, Ireneusz
Mesoscale and Nanoscale Physics
The transport across a Kondo-correlated quantum dot coupled to two leads with independent temperatures and chemical potentials is studied using a controlled non-perturbative, and in this sense exact numeric treatment based on a hybrid numerical renormalization group combined with time-dependent density matrix renormalization group (NRG-tDMRG). We find a peak in the conductance at finite voltage bias vs. the temperature gradient $ΔT = T_R - T_L$ across left and right lead. We then focus predominantly on zero voltage bias but finite $ΔT$ far beyond linear response. We reveal the dependence of the characteristic zero-bias conductance on the individual lead temperatures. We find that the finite-$ΔT$ data behaves quantitatively similar to linear response with an effective equilibrium temperature derived from the different lead temperatures. The regime of sign changes in the Seebeck coefficient, signaling the presence of Kondo correlations, and its dependence on the individual lead temperatures provide a complete picture of the Kondo regime in the presence of finite temperature gradients. The results from the zero-bias conductance and Seebeck coefficient studies unveil an approximate `Kondo circle' in the $T_L/T_R$ plane as the regime within which the Kondo correlations dominate. We also study the heat current and the corresponding heat conductance vs. finite $ΔT$. We provide a polynomial fit for our numerical results for the thermocurrent as a function of the individual lead temperatures which may be used to fit experimental data in the Kondo regime.
title Nonequilibrium steady-state thermoelectrics of Kondo-correlated quantum dots
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2409.03102