Orbital Hall effect in mesoscopic devices

Diego B. Fonseca, Lucas L. A. Pereira, Anderson L. R. Barbosa

Published 2023-05-02Version 1

We investigate the orbital Hall effect through a disordered mesoscopic device with momentum-space orbital texture that is connected to four semi-infinite terminals embedded in the Landauer-B\"uttiker configuration for quantum transport. We present clear analytical and numerical evidence that the orbital Hall current fluctuations are universals (as with spin Hall current fluctuations). The universal orbital Hall current fluctuations (UOCF) exhibit two universal numbers of 0.36 and 0.18 for weak and strong spin-orbit coupling, respectively. The universal numbers are obtained by analytical calculation via random matrix theory and are supported by numerical calculations based on the tight-binding model. Furthermore, the UOCF lead to two universal relationships between the orbital Hall angle and conductivity. Finally, we confront the two universal relations with experimental data of the orbital Hall angle, which shows good concordance between theory and experiment.