Illuminating the Surface Spin Texture of the Giant-Rashba Quantum-Well System $\mathrm{Bi}/\mathrm{Ag}(111)$ by Circularly Polarized Photoemission

Illuminating the Surface Spin Texture of the Giant-Rashba Quantum-Well System $Bi / Ag (111)$ by Circularly Polarized Photoemission

Guang Bian, Longxiang Zhang, Yang Liu, T. Miller, and T.-C. Chiang

Phys. Rev. Lett. 108, 186403 – Published 2 May 2012

Abstract

We have mapped out the spin texture of a $Bi / Ag$ surface alloy prepared on a thin Ag film by circularly polarized angle-resolved photoemission spectroscopy. A term proportional to $\nabla \cdot A$ in the interaction Hamiltonian gives rise to strong surface photoexcitation, which interferes with a Rashba contribution to yield a pronounced circular dichroic effect in $Bi / Ag$ . The dipole transition, often taken to be the only important photoexcitation mechanism, is actually negligible. A parameter-free calculation yields a dichroic pattern in excellent agreement with experiment.

Received 2 February 2012

DOI:https://doi.org/10.1103/PhysRevLett.108.186403

Authors & Affiliations

Guang Bian, Longxiang Zhang, Yang Liu, T. Miller, and T.-C. Chiang

Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA
Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801-2902, USA