Ellguth M, Tusche C, Kirschner J. Optical Generation of Hot Spin-Polarized Electrons from a Ferromagnetic Two-Dimensional Electron Gas.
PHYSICAL REVIEW LETTERS 2015;
115:266801. [PMID:
26765012 DOI:
10.1103/physrevlett.115.266801]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Indexed: 06/05/2023]
Abstract
Linearly polarized light with an energy of 3.1 eV has been used to excite highly spin-polarized electrons in an ultrathin film of face-centered-tetragonal cobalt to majority-spin quantum well states (QWS) derived from an sp band at the border of the Brillouin zone. The spin-selective excitation process has been studied by spin- and momentum-resolved two-photon photoemission. Analyzing the photoemission patterns in two-dimensional momentum planes, we find that the optically driven transition from the valence band to the QWS acts almost exclusively on majority-spin electrons. The mechanism providing the high spin polarization is discussed by the help of a density-functional theory calculation. Additionally, a sizable effect of spin-orbit coupling for the QWS is evidenced.
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