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Surface reconstructions and transport of epitaxial PtLuSb (001) thin films grown by MBE

This work presents the surface reconstructions and transport properties of the topological insulator PtLuSb grown on Al0.1In0.9Sb/GaAs (001). Two stable surface reconstructions, (1x3) and c(2x2), were observed on PtLuSb (001) surfaces. Antimony-dimerization was determined to be the nature of the (1x3) surface reconstruction as evidenced by chemical binding energy shifts in the antimony 4d core-level for surface bonding components. The two surface reconstructions were studied as a function of Sb4 overpressure and substrate temperature to create a reconstruction phase diagram. From this reconstruction phase diagram, a growth window from 320 °C to 380 °C using an antimony overpressure was identified. Within this window, the highest quality films were grown at a growth temperature of 380 °C. These films exhibited lower p-type carrier concentrations as well as relatively high hole mobilities.