Axially lattice-matched wurtzite/rock-salt GaAs/Pb1-xSnxTe nanowires

Abstract

We investigate the full and half-shells of Pb_1-xSn_xTe topological crystalline insulator deposited by molecular beam epitaxy on the sidewalls of wurtzite GaAs nanowires (NWs). Due to the distinct orientation of the IV-VI shell with respect to the III-V core the lattice mismatch between both materials along the nanowire axis is less than 4%. The Pb_1-xSn_xTe solid solution is chosen due to the topological crystalline insulator properties above some critical concentrations of Sn (x ≥ 0.36). The IV-VI shells are grown with different compositions spanning from binary SnTe, through Pb_1-xSn_xTe with decreasing x value down to binary PbTe (x = 0). The samples are analysed by scanning transmission electron microscopy, which reveals the presence of (110) or (100) oriented binary PbTe and (100) Pb_1-xSn_xTe on the sidewalls of wurtzite GaAs NWs.