Relaxation dynamics in correlated quantum dots

Andergassen, Sabine; Schuricht, Dirk; Pletyukhov, Mikhail; Schoeller, Herbert

doi:10.1063/1.4903140

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…Specifically, we investigate the nonequilibrium steady state dynamics of a SIAM, which is driven by the coupling to two leads at different chemical potentials, caused by an external bias voltage φ. Impurity models in such a setup were considered already by many groups, numerically as well as analytically. [38][39][40] To give a brief non-exhaustive overview, different techniques employed are the noncrossing approximation, [41][42][43] real-time diagrammatic methods, 44 Keldysh perturbation theory, 45 Keldysh effective field theory, 46,47 dual fermions, 48,49 perturbative RG, 50,51 flow equations, 52,53 functional RG, 54,55 real-time RG, [56][57][58][59] time-dependent density matrix RG, [60][61][62][63] NRG, [64][65][66] Monte Carlo methods, [67][68][69] as well as cluster approaches. 70 The properties of the correlated impurity have been established in certain limits, for example for high temperatures T ≫ T K or high biases φ ≫ T K , where the Kondo effect is strongly suppressed by decoherence and the problem reduces to a weak coupling one.…”

Section: Introductionmentioning

confidence: 99%

Auxiliary master equation approach within matrix product states: Spectral properties of the nonequilibrium Anderson impurity model

et al. 2015

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Within the recently introduced auxiliary master equation approach it is possible to address steady state properties of strongly correlated impurity models, small molecules or clusters efficiently and with high accuracy. It is particularly suited for dynamical mean field theory in the nonequilibrium as well as in the equilibrium case. The method is based on the solution of an auxiliary open quantum system, which can be made quickly equivalent to the original impurity problem. In its first implementation a Krylov space method was employed. Here, we aim at extending the capabilities of the approach by adopting matrix product states for the solution of the corresponding auxiliary quantum master equation. This allows for a drastic increase in accuracy and permits us to access the Kondo regime for large values of the interaction. In particular, we investigate the nonequilibrium steady state of a single impurity Anderson model and focus on the spectral properties for temperatures T below the Kondo temperature TK and for small bias voltages φ. For the two cases considered, with T ≈ TK/4 and T ≈ TK/10 we find a clear splitting of the Kondo resonance into a two-peak structure for φ close above TK. In the equilibrium case (φ = 0) and for T ≈ TK/4, the obtained spectral function essentially coincides with the one from numerical renormalization group.

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Section: Introductionmentioning

confidence: 99%

Auxiliary master equation approach within matrix product states: Spectral properties of the nonequilibrium Anderson impurity model

et al. 2015

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“…Introduction -Since the times of Kondo [1] and Anderson [2], physicists have been fascinated by the possible effects of embedding a correlated quantum impurity in a metallic host [3][4][5][6]. Recently, a lot of work in this area has also concentrated around the Interacting Resonant Level model (IRLM) [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]; first introduced in 1978 [7] as formally equivalent to the anisotropic Kondo model, it gained a lot of interest in its own right since various exact solutions out of equilibrium were proposed for it [13][14][15]. Despite a lot of progress being made on non-equilibrium transport in the IRLM [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], there remains open questions about equilibrium properties.…”

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confidence: 99%

Local density of states of the interacting resonant level model at zero temperature

2022

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We present results of the impurity local density of states of the interacting resonant level model at zero temperature. We concentrate on low-energy properties and predominantly use the numerical renormalisation group technique. As interaction is increased, we find that the resonance peak at zero energy disappears, while two new peaks at finite energy emerge. This is in the absence of any field breaking the resonance. We further show that the height of the spectral function does not scale in the same way as the width, and in fact defines a second distinct exponent. We back up our results with analytic strong-coupling calculations as well as an analytic diagrammatic renormalisation group calculation that rather surprisingly gets the second exponent exactly, even for strong interactions.

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Thermoelectric response of a correlated impurity in the nonequilibrium Kondo regime

et al. 2016

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We study nonequilibrium thermoelectric transport properties of a correlated impurity connected to two leads for temperatures below the Kondo scale. At finite bias, for which a current flows across the leads, we investigate the differential response of the current to a temperature gradient. In particular, we compare the influence of a bias voltage and of a finite temperature on this thermoelectric response. This is of interest from a fundamental point of view to better understand the two different decoherence mechanisms produced by a bias voltage and by temperature. Our results show that in this respect the thermoelectric response behaves differently from the electric conductance. In particular, while the latter displays a similar qualitative behavior as a function of voltage and temperature, both in theoretical and experimental investigations, qualitative differences occur in the case of the thermoelectric response. In order to understand this effect, we analyze the different contributions in connection to the behavior of the impurity spectral function versus temperature. Especially in the regime of strong interactions and large enough bias voltages we obtain a simple picture based on the asymmetric suppression or enhancement of the split Kondo peaks as a function of the temperature gradient. Besides the academic interest, these studies could additionally provide valuable information to assess the applicability of quantum dot devices as responsive nanoscale temperature sensors.

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Relaxation dynamics in correlated quantum dots

Cited by 3 publications

References 7 publications

Auxiliary master equation approach within matrix product states: Spectral properties of the nonequilibrium Anderson impurity model

Auxiliary master equation approach within matrix product states: Spectral properties of the nonequilibrium Anderson impurity model

Local density of states of the interacting resonant level model at zero temperature

Thermoelectric response of a correlated impurity in the nonequilibrium Kondo regime

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