TY  - JOUR
AU  - Seifert, Tom S.
AU  - Go, Dongwook
AU  - Hayashi, Hiroki
AU  - Rouzegar, Reza
AU  - Freimuth, Frank
AU  - Ando, Kazuya
AU  - Mokrousov, Yuriy
AU  - Kampfrath, Tobias
TI  - Time-domain observation of ballistic orbital-angular-momentum currents with giant relaxation length in tungsten
JO  - Nature nanotechnology
VL  - 18
IS  - 10
SN  - 1748-3387
CY  - London [u.a.]
PB  - Nature Publishing Group
M1  - FZJ-2023-05909
SP  - 1132 - 1138
PY  - 2023
AB  - 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/SiO2 interface, the L flow is efficiently converted into a charge current by the inverse orbital Rashba–Edelstein effect, consistent with ab initio calculations. Our findings establish orbitronic materials with long-distance ballistic L transport as possible candidates for future ultrafast devices and an approach to discriminate Hall-like and Rashba–Edelstein-like conversion processes.
LB  - PUB:(DE-HGF)16
C6  - 37550573
UR  - <Go to ISI:>//WOS:001043662300004
DO  - DOI:10.1038/s41565-023-01470-8
UR  - https://juser.fz-juelich.de/record/1020242
ER  -