Charge redistribution in correlated heterostuctures within nonequilibrium real-space dynamical mean-field theory

Abstract

We address the steady-state behavior of a system consisting of several correlated monoatomic layers sandwiched between two metallic leads under the influence of a bias voltage. In particular, we investigate the interplay of the local Hubbard and the long-range Coulomb interaction on the charge redistribution at the interface, in the paramagnetic regime of the system. We provide a detailed study of the importance of the various system parameters, like Hubbard U , lead-correlated region coupling strength, and the applied voltage on the charge distribution in the correlated region and in the adjacent parts of the leads. In addition, we also present results for the steady-state current density and double occupancies. Our results indicate that, in a certain range of parameters, the charge on the two layers at the interface between the leads and the correlated region display opposite signs producing a dipolelike layer at the interface. Our results are obtained within nonequilibrium (steady-state) real-space dynamical mean-field theory (R-DMFT), with a self-consistent treatment of the long-range part of the Coulomb interaction by means of the Poisson equation. The latter is solved by the Newton-Raphson method and we find that this significantly reduces the computational cost compared to existing treatment. As impurity solver for R-DMFT we use the auxiliary master equation approach (AMEA), which addresses the impurity problem within a finite auxiliary system coupled to Markovian environments.

A many-body approach to transport in quantum systems: from the transient regime to the stationary state

“…Transient dynamics in quantum correlated lattice networks can also be resolved by using the dynamical mean-field theory (DMFT) [107,108], which uses a local impurity model as its starting point, and constructs an expansion in terms of the coupling between the impurity and its dynamical environment. This expansion can also be applied in the context of quantum transport [109][110][111]. Another widely used method is the density matrix renormalization group (DMRG) and its timedependent extension [112][113][114].…”

A many-body approach to transport in quantum systems: From the transient regime to the stationary state

“…Transient dynamics in quantum correlated lattice networks can also be resolved by using the dynamical mean-field theory (DMFT) [108,109], which uses a local impurity model as its starting point, and constructs an expansion in terms of the coupling between the impurity and its dynamical environment. This expansion can also be applied in the context of quantum transport [110][111][112]. Another widely used method is the density matrix renormalization group (DMRG) and its time-dependent extension [113][114][115].…”

A quantum Boltzmann equation for strongly correlated electrons

“…This implicit scheme allows a non-perturbative evaluation of the QBE, provided that an efficient numerical description of a NESS is available: To evaluate Σness k,ω F (•, t), ... and A k (ω, t) = Âness k,ω F (•, t), ... for a given distribution function F , we choose an auxiliary steady state system with reservoir self-energy ΓR k (ω) = Γ R k (ω, t), while the bath occupation function, and hence Γ< k (ω) is treated as a free parameter. The latter is chosen such that the solution Fk (ω) gives the prescribed F k (ω, t), after which the outcomes Āk (ω) and Σint,k (ω) are used to evaluate (38) and (39). In particular, within non-equilibrium DMFT, where only local self-energies need to be evaluated in a quantum impurity model, several promising non-perturbative techniques are available that can directly target such non-equilibrium states (see discussion in Sec.…”

“…This allows to consistently combine the QBE with non-perturbative methods which have been developed to study true non-equilibrium steady states within DMFT. [37][38][39][40][41][42][43] The paper is organized as follows: In section II, we present the formulation of a non-perturbative QBE which is consistent with non-equilibrium DMFT. In Sec.…”