Time-domain observation of ballistic orbital-angular-momentum currents with giant relaxation length in tungsten.

ABSTRACT: The emerging field of orbitronics exploits the electron orbital momentum L. Compared to spin-polarized electrons, L may allow the transfer of magnetic information with considerably higher density over longer distances in more materials. However, direct experimental observation of L currents, their extended propagation lengths and their conversion into charge currents has remained challenging. Here, we optically trigger ultrafast angular-momentum transport in Ni|W|SiO₂ thin-film stacks. The resulting terahertz charge-current bursts exhibit a marked delay and width that grow linearly with the W thickness. We consistently ascribe these observations to a ballistic L current from Ni through W with a giant decay length (~80 nm) and low velocity (~0.1 nm fs^-1). At the W/SiO<

SUBMITTER: Seifert TS 

PROVIDER: S-EPMC10575790 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature