Development of dual-beamline photoelectron momentum microscopy for valence orbital analysis

J Synchrotron Radiat. 2024 May 1;31(Pt 3):540-546. doi: 10.1107/S1600577524002406. Epub 2024 Apr 15.

Abstract

The soft X-ray photoelectron momentum microscopy (PMM) experimental station at the UVSOR Synchrotron Facility has been recently upgraded by additionally guiding vacuum ultraviolet (VUV) light in a normal-incidence configuration. PMM offers a very powerful tool for comprehensive electronic structure analyses in real and momentum spaces. In this work, a VUV beam with variable polarization in the normal-incidence geometry was obtained at the same sample position as the soft X-ray beam from BL6U by branching the VUV beamline BL7U. The valence electronic structure of the Au(111) surface was measured using horizontal and vertical linearly polarized (s-polarized) light excitations from BL7U in addition to horizontal linearly polarized (p-polarized) light excitations from BL6U. Such highly symmetric photoemission geometry with normal incidence offers direct access to atomic orbital information via photon polarization-dependent transition-matrix-element analysis.

Keywords: atomic orbital; electronic structure; photoelectron momentum microscopy; photoemission spectroscopy; photon polarization.