Spin Hall effect in a Doped Mott Insulator

TL;DR

This paper demonstrates the existence of conserved spin Hall currents in a doped Mott insulator without spin-orbit coupling, revealing a finite spin Hall conductivity even in insulating states, with implications for spintronics.

Contribution

It shows that a strongly correlated doped Mott insulator can host a conserved spin Hall effect independent of spin-orbit coupling, expanding understanding of spin transport in correlated systems.

Findings

Finite spin Hall conductivity in doped Mott insulators.

Coexistence of spin Hall and Nernst effects in the pseudogap phase.

Prediction of a spin Hall insulator state at strong magnetic fields.

Abstract

The existence of conserved spin Hall currents is shown in a strongly correlated system without involving spin-orbit coupling. The spin Hall conductivity is determined by intrinsic bulk properties, which remains finite even when the charge resistivity diverges in strong magnetic fields at zero temperature. The state in the latter limit corresponds to a spin Hall insulator. Such a system is a doped Mott insulator described by the phase string theory, and spin Hall effect is predicted to coexist with the Nernst effect to characterize the intrinsic properties of the low-temperature pseudogap phase. Possible applications in spintronics are also mentioned.