Controllable spin-current blockade in a Hubbard chain

TL;DR

This paper demonstrates how a controllable spin-dependent hopping in a Hubbard chain can selectively block spin current while allowing charge current, highlighting the role of spin-charge separation in transport phenomena.

Contribution

It introduces a model with tunable spin-dependent hopping in a Hubbard chain to control spin and charge transport, revealing a spin-current blockade mechanism.

Findings

Spin current can be selectively blocked without affecting charge current.

Spin-charge separation is crucial for the observed blockade.

The phenomenon can be used to directly observe spin-charge separation.

Abstract

We investigate the spin/charge transport in a one-dimensional strongly correlated system by using the adaptive time-dependent density-matrix renormalization group method. The model we consider is a non-half-filled Hubbard chain with a bond of controllable spin-dependent electron hoppings, which is found to cause a blockade of spin current with little influence on charge current. We have considered (1) the spread of a wave packet of both spin and charge in the Hubbard chain and (2) the spin and charge currents induced by a spin-dependent voltage bias that is applied to the ideal leads attached at the ends of this Hubbard chain. It is found that the spin-charge separation plays a crucial role in the spin-current blockade, and one may utilize this phenomenon to observe the spin-charge separation directly.