Studies of CoFeB crystalline structure grown on PbSnTe topological insulator substrate

TL;DR

This study demonstrates the first successful epitaxial growth of CoFeB layers on a PbSnTe topological insulator substrate using laser molecular beam epitaxy, revealing their crystalline structure and epitaxial relationship.

Contribution

It introduces a novel method for growing ferromagnetic layers on topological insulators and characterizes their crystalline and epitaxial properties.

Findings

CoFeB layers have a bcc crystal structure with (111) orientation.

Epitaxial relationship between CoFeB and PbSnTe was determined.

Substrate stoichiometry was confirmed through diffraction pattern analysis.

Abstract

Co40Fe40B20 layers were grown on the Pb0.71Sn0.29Te topological insulator substrates by laser molecular beam epitaxy (LMBE) method, and the growth conditions were studied. The possibility of growing epitaxial layers of a ferromagnet on the surface of a topological insulator was demonstrated for the first time. The Co40Fe40B20 layers obtained have a bcc crystal structure with a crystalline (111) plane parallel to the (111) PbSnTe plane. The use of three-dimensional mapping in the reciprocal space of reflection high electron diffraction (RHEED) patterns made it possible to determine the epitaxial relationship of main crystallographic axes between the film and the substrate of topological insulator. Quenching of some reflections in diffraction pattern allows confirmation of the substrate stoichiometry.