Time-Dependent DMRG Study on Quantum Dot under a Finite Bias Voltage

One of the main open problems in the field of transport in strongly interacting nanostructures is the understanding of currents beyond the linear response regime. In this work, we consider the single-impurity Anderson model and use the adaptive time-dependent density matrix renormalization group (tDMRG) method to compute real-time currents out of equilibrium. We first focus on the particle-hole symmetric point where Kondo correlations are the strongest and then extend the study of the nonequilibrium transport to the mixed-valence regime. As a main result, we present accurate data for the current-voltage characteristics of this model.

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“…(1) out of equilibrium and at V g = −U/2 were presented in Ref. 43 by Kirino et al for U/Γ ≤ 2.8 and in Ref. 38 for U/Γ = 3.125.…”

Section: Numerical Method: Dmrgmentioning

confidence: 90%

Real-time simulations of nonequilibrium transport in the single-impurity Anderson model

2009

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“…This technique is known to yield reliable results for a wide parameter range of one-dimensional models [12][13][14][24][25][26][27][28][29][30][31][32][33][34] and to agree with analytical data. 13 We focus on the particle-hole-symmetric point which shows the most pronounced many-body effects.…”

Section: Published By the American Physical Society Under The Terms Omentioning

confidence: 96%

Steady-state and quench-dependent relaxation of a quantum dot coupled to one-dimensional leads

et al. 2013

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We study the time evolution and steady state of the charge current in a single-impurity Anderson model, using matrix product states techniques. A nonequilibrium situation is imposed by applying a bias voltage across one-dimensional tight-binding leads. Focusing on particle-hole symmetry, we extract current-voltage characteristics from universal low-bias up to high-bias regimes, where band effects start to play a dominant role. We discuss three quenches, which after strongly quench-dependent transients yield the same steady-state current. Among these quenches we identify those favorable for extracting steady-state observables. The period of short-time oscillations is shown to compare well to real-time renormalization group results for a simpler model of spinless fermions. We find indications that many-body effects play an important role at high-bias voltage and finite bandwidth of the metallic leads. The growth of entanglement entropy after a certain time scale ∝ −1 is the major limiting factor for calculating the time evolution. We show that the magnitude of the steady-state current positively correlates with entanglement entropy. The role of high-energy states for the steady-state current is explored by considering a damping term in the time evolution.

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“…V p ( k) is the hybridization potential between conduction electrons in the electrode and electrons in the center region. In the theory of Kubo formula with Keldysh Green function, the obtained density matrix does not depend on the split of the toal Hamiltonian [2,3].…”

Section: Models and Calculation Of DC Currentmentioning

confidence: 88%