Effect of electronic interactions on the persistent current in one-dimensional disordered rings

TL;DR

This study investigates how electronic interactions influence persistent currents in disordered one-dimensional rings, revealing regimes where interactions enhance current magnitude, with implications for understanding quantum transport.

Contribution

It provides a detailed analysis of the effect of electron-electron interactions on persistent currents in disordered rings using DMRG, including analytical insights into different interaction regimes.

Findings

Weak interactions can increase persistent current in disordered rings.

Strong interactions lead to a decrease in current depending on filling.

Localization length studies confirm current enhancement at moderate interactions.

Abstract

The persistent current is here studied in one-dimensional disordered rings that contain interacting electrons. We used the density matrix renormalization group algorithms in order to compute the stiffness, a measure that gives the magnitude of the persistent currents as a function of the boundary conditions for different sets of both interaction and disorder characteristics. In contrast to its non-interacting value, an increase in the stiffness parameter was observed for systems at and off half-filling for weak interactions and non-zero disorders. Within the strong interaction limit, the decrease in stiffness depends on the filling and an analytical approach is developed to recover the observed behaviors. This is required in order to understand its mechanisms. Finally, the study of the localization length confirms the enhancement of the persistent current for moderate interactions when disorders are present at half-filling. Our results reveal two different regimes, one for weak and one for strong interactions at and off half-filling.