Cancellation theorem breaking and resonant spin-tensor Hall conductivity in higher-rank spin-tensor Hall effects

TL;DR

This paper investigates the cancellation theorem in higher-rank spin-tensor Hall effects, revealing conditions under which the spin-tensor Hall conductivity can diverge or exhibit observable resonances, advancing understanding of spin transport in larger spin systems.

Contribution

It demonstrates that the universal intrinsic spin-tensor Hall conductivity can diverge or resonate, providing new insights into spin transport phenomena beyond traditional spin Hall effects.

Findings

Rank-2 spin-tensor current can diverge due to interbranch and intrabranch transitions.

Universal spin-tensor Hall effect is not observable in finite systems.

Resonance of spin-tensor Hall conductivity occurs at Landau level crossings.

Abstract

With recent advances in simulating quantum phenomena in cold atoms, the higher-rank spin tensor Hall effect was discovered in larger spin systems with spin-tensor-momentum coupling, which is an extension of the celebrated spin Hall effects in larger spins. Previously, it has been proposed that a 2D electron gas with Rashba spin-orbit coupling can generate dissipationless transverse spin current, namely the spin Hall effect. However, later work showed that the spin current is canceled by vertex correction, which was subsequently proven by a cancellation theorem that does not depend on any assumptions related to the scattering mechanism, the strength of spin-orbit coupling, or the Fermi energy. While the recent proposal demonstrates a universal intrinsic spin-tensor Hall conductivity, it is unclear if it vanishes similarly to the spin Hall effect. In this work, we address this critical problem and show that the rank-2 spin-tensor current can be divergent by considering the contributions of both interbranch and intrabranch transitions, which resembles the quantum Hall effect in some sense. So the \textit{universal} spin-tensor Hall effect can not be observed in a system with finite size. However, we further show that there is an \textit{observable non-zero} resonance of spin-tensor Hall conductivity as the Landau levels cross under the magnetic field. Our work reveals interesting conductivity properties of larger-spin systems and will provide valuable guidance for experimental explorations of higher-rank spin-tensor Hall effects, as well as their potential device applications.