Electronic transport through correlated electron systems with nonhomogeneous charge orderings

TL;DR

This study investigates how various nonhomogeneous charge orderings in the Falicov-Kimball model affect electronic transport in heterostructures, revealing complex current behaviors and temperature-dependent phenomena.

Contribution

It introduces a combined computational approach to analyze transport in correlated electron systems with nonhomogeneous charge orderings, highlighting their impact on conductance and temperature effects.

Findings

Charge orderings can cause metallic or insulating transport.

Temperature induces transient phases affecting conductance.

Complex current-voltage behaviors emerge from multi-band transmission.

Abstract

The spinless Falicov-Kimball model exhibits outside the particle-hole symmetric point different stable nonhomogeneous charge orderings. These include the well known charge stripes and a variety of orderings with phase separated domains, which can significantly influence the charge transport through the correlated electron system. We show this by investigating a heterostructure, in which the Falicov-Kimball model on a finite two-dimensional lattice is located between two noninteracting semi-infinite leads. We use a combination of nonequilibrium Green's functions techniques with a sign-problem-free Monte Carlo method for finite temperatures or a simulated annealing technique for the ground state to address steady-state transport through the system. We show that different ground-state phases of the central system can lead to simple metallic-like or insulating charge transport characteristics, but also to more complicated current-voltage dependencies reflecting a multi-band character of the transmission function. Interestingly, with increasing temperature, the orderings tend to form transient phases before the system reaches the disordered phase. This leads to nontrivial temperature dependencies of the transmission function and charge current.