Quantum mechanical interpretation of the ultrafast all optical spin switching. (30th March 2017)

• Record Type: Journal Article
• Authors: Murakami, Mitsuko; Babyak, Zach; Giocolo, Michael; Zhang, G P
• Is Part Of: Journal of physics. Volume 29:Number 18(2017)
• Publication Date: 2017-03-30
• Subjects: spin switching -- ultrafast magnetism -- femtosecond lasers; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa6558
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The all-optical spin switching induced by an intense (∼TW cm −2 ), near-infrared (775 nm), ultrashort (∼100 fs) circularly-polarized laser pulse is studied based on the spin–orbit coupled Heisenberg model. We find that the magnetic spin momentum undergoes an oscillation in time during the interaction with a driving laser pulse, which can be explained as a classical counterpart of the Rabi oscillation associated with a spin–orbit coupling. The optimal spin reversal is achieved by adjusting the pulse duration to one half the Rabi oscillation period. A successive spin reversal by a delayed pulse is possible if it has the opposite helicity and a shorter duration relative to the first pulse. Moreover, inclusion of an exchange interaction term in the Hamiltonian leads to a precession of the magnetic spin momentum that lasts even after the driving laser pulse turns off. This spin precession is stronger in antiferromagnets than ferrimagnets.