Features of spin-charge separation in the equilibrium conductance through finite rings

TL;DR

This paper investigates how spin-charge separation affects the conductance in finite quantum rings modeled by the $t-J$ model, identifying specific magnetic flux values that cause conductance dips, with potential experimental implications.

Contribution

It analytically identifies flux values causing conductance suppression due to spin-charge separation and numerically confirms these effects at zero temperature.

Findings

Conductance dips occur at specific flux values due to spin-charge separation.

Numerical results show conductance depression at half filling.

Results are relevant for experimental realization of quantum dot rings.

Abstract

We calculate the conductance through rings with few sites $L$ described by the $t-J$ model, threaded by a magnetic flux $\Phi$ and weakly coupled to conducting leads at two arbitrary sites. The model can describe a circular array of quantum dots with large charging energy $U$ in comparison with the nearest-neighbor hopping $t$. We determine analytically the particular values of $\Phi$ for which a depression of the transmittance is expected as a consequence of spin-charge separation. We show numerically that the equilibrium conductance at zero temperature is depressed at those particular values of $\Phi $ for most systems, in particular at half filling, which might be easier to realize experimentally.