Theory of circular dichroism in angle- and spin-resolved photoemission from the surface state on Bi(111)

TL;DR

This paper develops an ab initio theory to analyze circular dichroism in photoemission from Bi(111), highlighting the role of spin structure, photon energy dependence, and challenges in measuring orbital angular momentum.

Contribution

It introduces a comprehensive ab initio framework for understanding CD in photoemission from surface states, considering spin and azimuthal symmetry effects.

Findings

Strong photon energy dependence observed in ultraviolet range

Differences between initial state spin polarization and spin photocurrent highlighted

Symmetry analysis of azimuthal CD distribution for various spin orientations

Abstract

Circular dichroism (CD) of photoemission from a surface state on Bi(111) is considered within an {\it ab initio} one-step theory of photoemission. The symmetry of the azimuthal distribution of CD for different spin directions is discussed in terms of the spin structure of the initial states. Both normal and off-normal light incidence are considered. Strong photon energy dependence of photoemission in the ultraviolet range is observed. The principal difference between the initial state spin polarization and the spin photocurrent is emphasized and problems with revealing the orbital angular moment with photoemission are pointed to.