Ab initio investigation of light-induced relativistic spin-flip effects in magneto-optics
2015 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 91, no 17, 174415Article in journal (Refereed) Published
Excitation of a metallic ferromagnet such as Ni with an intensive femtosecond laser pulse causes an ultrafast demagnetization within approximately 300 fs. It was proposed that the ultrafast demagnetization measured in femtosecond magneto-optical experiments could be due to relativistic light-induced processes. We perform an ab initio investigation of the influence of relativistic effects on the magneto-optical response of Ni. To this end, first, we develop a response theory formulation of the additional appearing ultrarelativistic terms in the Foldy-Wouthuysen transformed Dirac Hamiltonian due to the electromagnetic field, and second, we compute the influence of relativistic light-induced spin-flip transitions on the magneto-optics. Our ab initio calculations of relativistic spin-flip optical excitations predict that these can give only a very small contribution (<= 0.1%) to the laser-induced magnetization change in Ni.
Place, publisher, year, edition, pages
2015. Vol. 91, no 17, 174415
IdentifiersURN: urn:nbn:se:uu:diva-256238DOI: 10.1103/PhysRevB.91.174415ISI: 000354555300004OAI: oai:DiVA.org:uu-256238DiVA: diva2:826091
FunderSwedish Research Council