Length-Dependent Conductance of a Spin-Incoherent Hubbard chain; Monte Carlo Calculations

TL;DR

This paper investigates how the electrical conductance of a short spin-incoherent Hubbard chain varies with chain length using quantum Monte Carlo methods, revealing a rapid decrease in conductance unlike the Luttinger liquid regime.

Contribution

It provides the first detailed Monte Carlo analysis of length-dependent conductance in spin-incoherent Hubbard chains, highlighting differences from Luttinger liquid behavior.

Findings

Conductance decreases rapidly with chain length in the spin-incoherent regime.

For a four-site chain, conductance approaches approximately 150 e^2/h.

Contact scattering contributes significantly to overall resistance.

Abstract

The dc conductance of a short spin-incoherent Hubbard chain coupled to leads is investigated using quantum Monte Carlo calculations. In contrast with the Luttinger liquid regime, where the conductance is equal to the noninteracting value, the spin-incoherent regime displays a conductance that decreases rapidly with chain length down to a value of roughly 1.5e2/h for a four site chain followed by a slower decrease for longer chains. We also discuss the resistance contribution from scattering in the contacts.