Seminars & Lectures
| * TITLE | Emergence of orbital angular momentum due to broken inversion symmetry and its contribution to Rashba-type splitting | ||||||
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| * DATE / TIME | 2011-12-16, 4:00 p.m. | ||||||
| * PLACE | ECC B244, Ewha Womans University | ||||||
| * ABSTRACT | |||||||
| We demonstrate that the chiral orbital angular momentum (OAM) structure can emerge as a result of broken inversion symmetry especially at the metal surfaces. The surface-normal electric field is responsible for chiral OAM states even if spin-orbit interaction is negligible. Such chiral OAM structure can be measured by a circular dichroism (CD) in angle-resolved photoemission spectroscopy (ARPES). To confirm the existence of OAM and its detection by CD-ARPES, we perform simulation of CD-ARPES for Cu surface states by first-principles calculation and the results agree well with our CD-ARPES experiment. Addition of the spin-orbit interaction to the chiral OAM structure produces a chiral spin angular momentum (SAM) pattern and the corresponding Rashba-type band splitting. We assert that OAM polarization should be a more widespread feature than the chiral spin structure which requires strong spin-orbit coupling. | |||||||
