X-Ray Standing-Wave Investigations of Valence Electronic Structure

Published

September 1, 2001

Author(s)

Joseph C. Woicik, E J. Nelson, D Heskett, J Warner, L E. Berman, B A. Karlin, I A. Vartanyants, M Z. Hasan, T Kendelewicz, Z -. Shen, P Pianetta

Abstract

We have examined the valance-electron emission from Cu, Ge, GaAs, InP, and NiO single crystals under the condition of strong x-ray Bragg reflection; i.e., in the presence of the spatially modulated x-ray standing-wave interference field that is produced by the superposition of the incident and reflected x-ray beams. These crystals span the entire metallic, covalent, and ionic range of solid-state bonding. It is demonstrated that the valence-electron emission is closely coupled to the atomic cores, even for electron states close to a metallic Fermi edge. Using the bond-orbital approximation, the x-ray standing-wave structure factor for valence-electron emission is derived in terms of the bond polarities and photoionization cross sections of the atoms within the crystalline-unit cell and compared to experiment. Additionally, we demonstrate that by exploiting the spatial dependence of the electric-field intensity under Bragg condition, site-specific valance-electronic structure may be obtained. The technique is demonstrated for GaAs and NiO.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Volume

64

Issue

No. 12

Pub Type

Journals

Keywords

Bragg reflection, crystalline-unit cell, valance-electron, x-ray standing wave

Citation

Woicik, J. , Nelson, E. , Heskett, D. , Warner, J. , Berman, L. , Karlin, B. , Vartanyants, I. , Hasan, M. , Kendelewicz, T. , Shen, Z. and Pianetta, P. (2001), X-Ray Standing-Wave Investigations of Valence Electronic Structure, Physical Review B (Condensed Matter and Materials Physics) (Accessed April 24, 2024)