Distortion-free sampling of ultrabroadband terahertz electric fields by interfacial spin accumulation.

ABSTRACT: In spintronics, FM|HM stacks consisting of a ferromagnetic-metal (FM) and a heavy-metal (HM) layer are model systems for spin transport and spin-charge interconversion. To explore their potential as detectors for ultrabroadband terahertz electromagnetic pulses, we measure the transient optical birefringence the terahertz field induces. Notably, the signal component linear in the FM magnetization agrees excellently with the shape of the incident terahertz electric field at 1 to 13 terahertz and beyond. Analysis indicates that the birefringence arises from the terahertz-field-driven spin accumulation at the FM/HM interface through the spin Rashba-Edelstein effect (SREE). Because of spin-momentum locking, the SREE decays by electron momentum relaxation in <10 femtoseconds, substantially faste

SUBMITTER: Chekhov AL 

PROVIDER: S-EPMC11927612 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature