@article{74a266e8c8414388a8fa4fdd38f0451b,
title = "Composition-dependent structural transition in epitaxial Bi1-xSbx thin films on Si(111)",
abstract = "Bismuth-antimony alloys (Bi1-xSbx) are topological insulators between 7 and 22\% Sb in bulk crystals, with an unusually high conductivity suitable for spin-orbit torque applications. Reducing the thickness of epitaxial Bi1-xSbx films is expected to increase the maximum band gap through quantum confinement, which may improve isolation of topological surface-state transport. Like Bi(001) on Si(111), Bi1-xSbx has been predicted to form a black phosphoruslike allotrope with unique electronic properties in nanoscale films; however, the impact of Sb alloying on both the bulklike and nanoscale crystal structures on Si(111) is currently unknown. Here we demonstrate that the allotropic transition in ultrathin epitaxial Bi1-xSbx films on Si(111) is suppressed above 8-9\% Sb, resulting in an unexpected (012) orientation within the topologically insulating regime. The metallic temperature-dependent conductivity associated with surface states in Bi(001) was not observed in the Bi1-xSbx(012) films, suggesting that the (012) orientation may significantly reduce surface-state transport. Growth on a Bi(001) buffer layer may prevent this orientation transition. Finally, we demonstrate that Sb alloying improves the continuity and quality of nanoscale Bi1-xSbx(012) films in the thickness regime expected for the black phosphorus allotrope, suggesting a promising route to large-area growth of puckered-layer two-dimensional Bi1-xSbx, which will be necessary to harness its unique electronic properties in practical applications.",
author = "Walker, \{Emily S.\} and Sarah Muschinske and Brennan, \{Christopher J.\} and Na, \{Seung Ryul\} and Tanuj Trivedi and March, \{Stephen D.\} and Yukun Sun and Tianhao Yang and Alice Yau and Daehwan Jung and Briggs, \{Andrew F.\} and Krivoy, \{Erica M.\} and Lee, \{Minjoo L.\} and Liechti, \{Kenneth M.\} and Yu, \{Edward T.\} and Deji Akinwande and Bank, \{Seth R.\}",
note = "This work was primarily supported by both the Texas Instruments Semiconductor Research Corporation Graduate Fellowship Program and the National Science Foundation through the Center for Dynamics and Control of Materials, an NSF MRSEC under Cooperative Agreement No. DMR-1720595. The authors would like to acknowledge Dr. H. Celio from the Texas Materials Institute at the University of Texas at Austin for assistance with x-ray photoelectron spectroscopy, and Prof. D. Milliron and C. Staller from the Department of Chemical Engineering at the University of Texas at Austin for assistance with electrical measurements. This work was primarily supported by both the Texas Instruments Semiconductor Research Corporation Graduate Fellowship Program and the National Science Foundation through the Center for Dynamics and Control of Materials, an NSF MRSEC under Cooperative Agreement No. DMR-1720595. The authors would like to acknowledge Dr. H. Celio from the Texas Materials Institute at the University of Texas at Austin for assistance with x-ray photoelectron spectroscopy, and Prof. D. Milliron and C. Staller from the Department of Chemical Engineering at the University of Texas at Austin for assistance with electrical measurements.",
year = "2019",
month = jun,
day = "7",
doi = "10.1103/PhysRevMaterials.3.064201",
language = "English (US)",
volume = "3",
journal = "Physical Review Materials",
issn = "2475-9953",
publisher = "American Physical Society",
number = "6",
}