Effect of electron transport on demagnetization on the shortest time scale
Abstract
It is generally believed that there are at least two ways to use an ultrafast laser pulse to demagnetize a magnetic sample. One is to directly photo-demagnetize the system through spin-orbit coupling (SOC), and the other is to utilize ultrafast hot electron transport without SOC. The challenge is that these two processes are entangled on the same time scale. However, we do not even know how fast electrons move under laser excitation, nor far they move. Here we carry out a first-principles time-dependent calculation to investigate how fast electrons actually move under laser excitation, and how large the electron transport affects demagnetization on the shortest time scale. To take into account the transport effect, we implement the intraband transition in our theory. For bulk fcc Ni, we find the effect of spin transport on demagnetization to be extremely small, no more than 1%.
Supported by the U.S. Department of Energy under Contract No. DE-FG02-06ER46304.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MARG70150Z