XPS of Electronic Structure of Ferroelectric Sn₂P₂S₆ Crystals

Abstract

The electronic structure of the ferroelectric Sn ₂ P ₂ S ₆ single crystal is studied by X-ray photoelectron spectroscopy in both paraelectric and ferroelectric phases. The spectra were measured with monochromatized Al K_α radiation in the energy range 0–1400 eV. Experimental energies are compared with the results of theoretical ab initio calculations of the molecular model of the crystal. The electronic structure of the valence band (VB) is revealed. Ferroelectric phase transition changes atom's charge and bonds strength, electronic structure of VB, core levels (CL) lines width and chemical shifts for the Sn, P and S states which are crystallographic plane-dependent.

Keywords:

• Sn₂P₂S₆
• ferroelectric
• crystals
• XPS
• electronic structure

Acknowledgments

This work was performed with the financial support of the Lithuanian State Science and Studies Foundation and within the framework of the Lithuanian–Ukrainian project.