Spin Hall effect in electronic L\'evy glasses: Enhanced spin current generation in the superdiffusive regime

TL;DR

This study demonstrates that electronic Lévý glasses can significantly enhance spin Hall currents in the superdiffusive regime, offering a promising platform for advanced spintronic device control.

Contribution

It introduces a novel approach to tuning spin Hall effects in Lévý glasses, revealing enhanced spin current generation in the superdiffusive regime compared to diffusive regimes.

Findings

Spin Hall angle reaches 30% in the superdiffusive regime.

Low charge current yields large spin Hall current in the superdiffusive regime.

Transport regimes can be tuned by adjusting Fermi energy.

Abstract

In spintronics, both electronic charge and spin are used to process and store information. Generation, manipulation, and detection of spin currents are essential for the development of next-generation spintronic technologies. Here, we investigate the spin Hall effect in electronic L\'evy glasses composed of graphene ribbons with randomly distributed circular regions of high spin-orbit coupling. These systems exhibit two transport regimes that can be tuned by adjusting the Fermi energy. The superdiffusive regime is characterized by low Fermi energy, low resistivity, and low magnetoresistivity, resulting in a long spin diffusion length, in contrast to the diffusive regime. Employing the Landauer-B\"uttiker approach in conjunction with numerically exact tight-binding simulations, we compute spin-resolved transmission coefficients to assess the spin Hall current and the spin Hall angle as functions of Fermi energy, spin-orbit coupling strength, and on-site electrostatic potential. Our findings reveal that, in the superdiffusive regime, a low charge current can be converted into a large spin Hall current, whereas in the diffusive regime, the same charge current generates a modest spin Hall current. Moreover, we observe that the spin Hall angle can reach 30% in the superdiffusive regime, whereas in the diffusive regime it is only 5%. These results demonstrate that electronic L\'evy glasses provide a versatile platform for controlling spin transport and optimizing the spin Hall effect for spintronic applications.