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Crystal-momentum dispersion of ultrafast spin change in fcc Co.

ABSTRACT: Nearly twenty years ago, Beaurepaire and coworkers showed that when an ultrafast laser impinges on a ferromagnet, its spin moment undergoes a dramatic change, but how it works remains a mystery. While the current experiment is still unable to resolve the minute details of the spin change, crystal momentum-resolved techniques have long been used to analyze the charge dynamics in superconductors and strongly correlated materials. Here we extend it to probe spin moment change in the entire three-dimensional Brillouin zone for fcc Co. Our results indeed show a strong spin activity along the ? line, supporting a prior experimental finding. The spin active pockets coalesce into a series of spin surfaces that follow the Fermi surfaces. We predict two largest spin change pockets which have been elusive to experiments: one pocket is slightly below the ? line and the other is along the ? line and close to the L point. Our theory presents an opportunity for the time-, spin- and momentum-resolve photoemission technique.

SUBMITTER: Si MS

PROVIDER: S-EPMC4031477 | biostudies-literature | 2014 May

REPOSITORIES: biostudies-literature

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Crystal-momentum dispersion of ultrafast spin change in fcc Co.

Si M S MS Li J Y JY Yang D Z DZ Xue D S DS Zhang G P GP

Scientific reports 20140523

Nearly twenty years ago, Beaurepaire and coworkers showed that when an ultrafast laser impinges on a ferromagnet, its spin moment undergoes a dramatic change, but how it works remains a mystery. While the current experiment is still unable to resolve the minute details of the spin change, crystal momentum-resolved techniques have long been used to analyze the charge dynamics in superconductors and strongly correlated materials. Here we extend it to probe spin moment change in the entire three-di ...[more]

PMID: 24852331

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