Metallicity in Ultra-Thin Oxygen-Deficient SrTiO₃ Thin Films

2016/06/03 by Balakrishnan, Purnima P., Alaan, Urusa S., Gray, Matthew T. +1
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

paper · doi:10.48550/arxiv.1606.01211

Abstract

We report on the observation of metallic behavior in thin films of oxygen-deficient SrTiO₃ - down to 9 unit cells - when coherently strained on (001) SrTiO₃ or DyScO₃-buffered (001) SrTiO₃ substrates. These films have carrier concentrations of up to 2×10²² cm^-3 and mobilities of up to 19,000 cm²/V-s at 2 K. There exists a non-conducting layer in our SrTiO_3-δ films that is larger in films with lower carrier concentrations. This non-conducting layer can be attributed to a surface depletion layer due to a Fermi level pinning potential. The depletion width, transport, and structural properties are not greatly affected by the insertion of a DyScO₃ buffer between the SrTiO₃ film and SrTiO₃ substrate.

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