Evidence of SnSb2Te4 rocksalt metastable phase of thin films grown by pulsed laser deposition

BILOVOL, V.; UREÑA, A.M.; FONTANA, M.; ROCCA, J.

Chisinau

Conferencia; 9th International Conference on Amorphous and Nanostructured Chalcogenides (ANC 9); 2019

SnSb2Te4, an intermetallic compounds in the pseudobinary SnTe-Sb2Te3, looks as a promising candidate for phase-change material in non-volatile memories applications. Thin films having thickness from 50 to 150 nm were grown by pulsed laser deposition using SnSb2Te4 as structure of 21 R-type structure (R-3m) consisting of rocksalt-type blocks separated by van der Waals gap. While in thermal equilibrium this phase crystallizes into a complex cubic close-packed structure [1], the thin films obtained had a simple NaCl-structure (Fm-3m) (metastable phase) as it was deduced from conventional XRD measurements in grazing incidence of the investigated films. The metastable phase transitioned to the stable complex structure during the measurements of electrical resistance on temperature dependence. 119mSn conversion electron Mössbauer spectroscopy was used to investigate the local environment of Sn atoms in as made film. The existence of Sn(II) in a high symmetry site was found as expected for SnSb2Te4. Nevertheless, the dominant contribution was Sn(IV) attributed to SnO2 phase, evidencing an oxidation of the films surface. The evidence of the metastable NaCl-structure of GeSb2Te4 films induced by heating the amorphous film by laser irradiation were reported [2-4]. Nevertheless, reports about SnSb2Te4 film to date were not found.