Magneto-Optical Detection of the Orbital Hall Effect in Chromium*

The orbital Hall effect has been theoretically predicted but its direct observation is a challenge. Here, we report the magneto-optical detection of current-induced orbital accumulation at the surface of a light 3d transition metal, Cr [1]. The orbital polarization is in-plane, transverse to the current direction, and scales linearly with current density, consistent with the orbital Hall effect. Comparing the thickness-dependent magneto-optical measurements with ab initio calculations, we estimate an orbital diffusion length in Cr of 6.6 ± 0.6 nm. Along with Choi et al. study of the OHE in Ti [2], our work provides strong evidence for the orbital Hall effect.

References

[1]   I. Lyalin, S. Alikhah, M. Berritta, P. M. Oppeneer, and R. K. Kawakami, “Magneto-Optical Detection of the Orbital Hall Effect in Chromium”, Phys. Rev. Lett. 131, 156702 (2023).

[2]   Y.-G. Choi, D. Jo, K.-H. Ko, D. Go, K.-H. Kim, et al., “Observation of the orbital Hall effect in a light metal Ti”, Nature 619, 52 (2023).