Growth and characterization of the Zintl-phase SrAl₄ on LaAlO₃

Abstract

We present an experimental study of thin films of SrAl₄ on a LaAlO₃ substrate, with special emphasis on the Zintl-Klemm-type properties of the thin films that we grow using molecular beam epitaxy. We quantify the orientation and stoichiometry of the films and the surface morphology using reflection high energy electron diffraction (RHEED), x-ray diffraction (XRD) and atomic force microscopy (AFM). Furthermore, we present measurements of electronic properties using x-ray photoelectron spectroscopy (XPS) and ultraviolet spectroscopy (UPS). We determine the core level shifts due to the chemical environment in SrAl₄-films, which will underline the Zintl-Klemm character of the material. We measure the work function of (001)-oriented SrAl₄. Additionally we analyze the electronic transport properties of the grown thin films including the resistivity, carrier density and mobility.