Dielectric breakdown in spin polarized Mott insulator

TL;DR

This paper investigates dielectric breakdown in a spin-polarized Mott insulator using a one-dimensional Hubbard model, revealing how the threshold electric field depends on the charge gap and persists across different spin polarizations.

Contribution

It provides a combined numerical and analytical analysis of dielectric breakdown in spin-polarized Mott insulators, highlighting the dependence of the threshold field on the charge gap.

Findings

Threshold field scales as $F_{th} ightarrow riangle^{3/2}$

Decay rate of ground state into holon-doublon pairs can be accurately computed

Breakdown mechanism persists as magnetization decreases

Abstract

Nonlinear response of a Mott insulator to external electric field, corresponding to dielectric breakdown phenomenon, is studied within of a one-dimensional half-filled Hubbard model. It is shown that in the limit of nearly spin polarized insulator the decay rate of the ground state into excited holon-doublon pairs can be evaluated numerically as well to high accuracy analytically. Results show that the threshold field depends on the charge gap as $F_{th} \propto \Delta^{3/2}$. Numerical results on small systems indicate on the persistence of a similar mechanism for the breakdown for decreasing magnetization down to unpolarised system.