Nonequilibrium quantum dynamics of a charge carrier doped into a Mott insulator

TL;DR

This paper investigates the real-time nonequilibrium dynamics of a charge carrier in a Mott insulator under an electric field, revealing different transport regimes and spatial structures in ladder and 2D systems.

Contribution

It provides a comparative analysis of charge carrier dynamics in ladder and 2D Mott insulators under electric fields, highlighting the crossover between different resistivity regimes and associated spin polaron structures.

Findings

Observation of adiabatic and PDR regimes in both systems.

Emergence of NDR at large fields with distinct behaviors in ladder and 2D.

Change in spin polaron structure during the PDR to NDR crossover.

Abstract

We study real-time dynamics of a charge carrier introduced into undoped Mott insulator propagating under a constant electric field F on the t-J ladder and square lattice. We calculate quasistationary current. In both systems adiabatic regime is observed followed by the positive differential resistivity (PDR) at moderate fields where carrier mobility is determined. Quantitative differences between ladder and 2-dimensional (2D) system emerge when at large fields both systems enter negative differential resistivity (NDR) regime. In the ladder system Bloch-like oscillations prevail, while in 2D the current remains finite, proportional to 1/F. The crossover between PDR and NDR regime in 2D is accompanied by a change of the spatial structure of the propagating spin polaron.