Dimensional Crossover Driven by Electric Field (original) (raw)
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Dimensional Crossover Driven by an Electric Field
Physical Review Letters, 2012
We study the steady-state dynamics of the Hubbard model driven out-of-equilibrium by a constant electric field and coupled to a dissipative heat bath. For very strong field, we find a dimensional reduction: the system behaves as an equilibrium Hubbard model in lower dimensions. We derive steady-state equations for the dynamical mean-field theory in the presence of dissipation. We discuss how the electric field induced dimensional crossover affects the momentum resolved and integrated spectral functions, the energy distribution function, as well as the steady current in the non-linear regime.
Electric-Field-Driven Resistive Switching in the Dissipative Hubbard Model
Physical Review Letters, 2015
We study how strongly correlated electrons on a dissipative lattice evolve from equilibrium under a constant electric field, focusing on the extent of the linear regime and hysteretic non-linear effects at higher fields. We access the non-equilibrium steady states, non-perturbatively in both the field and the electronic interactions, by means of a non-equilibrium dynamical mean-field theory in the Coulomb gauge. The linear response regime, limited by Joule heating, breaks down at fields much smaller than the quasi-particle energy scale. For large electronic interactions, strong but experimentally accessible electric fields can induce a resistive switching by driving the strongly correlated metal into a Mott insulator. We predict a non-monotonic upper switching field due to an interplay of particle renormalization and the field-driven temperature. Hysteretic I-V curves suggest that the non-equilibrium current is carried through a spatially inhomogeneous metal-insulator mixed state.
Approach to a stationary state in a driven Hubbard model coupled to a thermostat
Physical Review B, 2012
We investigate the dynamics of the Hubbard model in a static electric field in order to identify the conditions to reach a non-equilibrium stationary state. We show that, for a generic electric field, the convergence to a stationary state requires the coupling to a thermostating bath absorbing the work done by the external field. Following the real-time dynamics of the system, we show that a non-equilibrium stationary state is reached for essentially any value of the coupling to the bath. We characterize the properties of such non-equilibrium stationary states by studying suitable physical observables, pointing out the existence of an analog of the Pomeranchuk effect as a function of the electric field. We map out a phase diagram in terms of dissipation and electric field strengths and identify the dissipation values in which steady current is largest for a given field.
U(1) slave-particle study of the finite-temperature doped Hubbard model in one and two dimensions
Annals of Physics, 2011
One-dimensional systems have unusual properties such as fractionalization of degrees of freedom. Possible extensions to higher dimensional systems have been considered in the literature. In this work we construct a mean field theory of the Hubbard model taking into account a separation of the degrees of freedom inspired by the one-dimensional case and study the finite-temperature phase diagram for the Hubbard chain and square lattice. The mean field variables are defined along the links of the underlying lattice. We obtain the spectral function and identify the regions of higher spectral weight with the fractionalized fermionic (spin) and bosonic (charge) excitations.
Thermodynamics and excitations of the one-dimensional Hubbard model
Physics Reports, 2000
We review fundamental issues arising in the exact solution of the one-dimensional Hubbard model. We perform a careful analysis of the Lieb-Wu equations, paying particular attention to so-called 'string solutions'. Two kinds of string solutions occur: Λ strings, related to spin degrees of freedom and k-Λ strings, describing spinless bound states of electrons. Whereas Λ strings were thoroughly studied in the literature, less is known about k-Λ strings. We carry out a thorough analytical and numerical analysis of k-Λ strings. We further review two different approaches to the thermodynamics of the Hubbard model, the Yang-Yang approach and the quantum transfer matrix approach, respectively. The Yang-Yang approach is based on strings, the quantum transfer matrix approach is not. We compare the results of both methods and show that they agree. Finally, we obtain the dispersion curves of all elementary excitations at zero magnetic field for the less than half-filled band by considering the zero temperature limit of the Yang-Yang approach.
Physical Review B, 2006
The BCS-BEC crossover within the two-dimensional attractive Hubbard model is studied by using the Cellular Dynamical Mean-Field Theory both in the normal and superconducting ground states. Short-range spatial correlations incorporated in this theory remove the normal-state quasiparticle peak and the first-order transition found in the Dynamical Mean-Field Theory, rendering the normal state crossover smooth. For U smaller than the bandwidth, pairing is driven by the potential energy, while in the opposite case it is driven by the kinetic energy, resembling a recent optical conductivity experiment in cuprates. Phase coherence leads to the appearance of a collective Bogoliubov mode in the density-density correlation function and to the sharpening of the spectral function.
Equilibrium and Dynamical Properties of the Boson Hubbard Model in One Dimension
Journal of Low Temperature Physics, 2005
We describe quantum monte carlo simulations of the static and dynamic properties of the one dimensional boson Hubbard model, emphasizing the extent to which an external confining potential modifies the behavior. While the superfluid-Mott insulator quantum phase transition no longer exists when the system is confined, Mott and superfluid regions persist locally in the system. We construct a 'state diagram' based on the local density and compressibility profiles. Solitons present in the dynamics of the unconfined system survive the addition of a trapping potential.
2011
We introduce a new class of exchange-correlation potentials for a static and time dependent Density Functional Theory of strongly correlated systems in 3D. The potentials are obtained via Dynamical Mean Field Theory and, for strong enough interactions, exhibit a discontinuity at half filling density, a signature of the Mott transition. For time dependent perturbations, the dynamics is described in the adiabatic local density approximation. Results from the new scheme compare very favorably to exact ones in clusters. As an application, we study Bloch oscillations in the 3D Hubbard model.
Feedback effects and the self-consistent Thouless criterion of the attractive Hubbard model
We propose a fully microscopic theory of the anomalous normal state of the attractive Hubbard model in the low-density limit that accounts for propagator renormalization. Our analytical conclusions, which focus on the thermodynamic instabilities contained in the self-consistent equations associated with our formulation, have been verified by our comprehensive numerical study of the same equations. The resulting theory is found to contain no transitions at non-zero temperatures for all finite lattices, and we have confirmed, using our numerical studies, that this behaviour persists in the thermodynamic limit for low-dimensional systems.