Weak antilocalization in selective-area grown Pb_1-xSn_xTe nanowire networks

Lead Tin Telluride (Pb_1-xSn_xTe) is predicted to be a topological crystalline insulator (TCI) [1], meaning that the surface states are protected by crystal symmetries. The topological phase transition from a trivial narrow bandgap semiconductor to a TCI can be controlled through the Pb/Sn ratio, and has been observed experimentally at Sn concentrations of 30-40% [2][3].

Hybrid TCI/superconductor nanowire networks are of interest for applications in quantum computation, as these are predicted to host non-abelian quasiparticles, such as Majorana fermions or parafermions [4]. Towards this goal, we use a pre-patterned SiNx mask on a InP(111) substrate for selective area growth of Pb_1-xSn_xTe by molecular beam epitaxy [5], and define Hall bar devices with side gates that allow for simultaneous Hall and field-effect measurements.

By investigating the low-temperature (magneto-)transport properties, a Hall mobility (135 cm²/Vs) and carrier density (4.7·10²⁰ cm^-3, similar to [2]) are obtained for pure SnTe nanowires. Moreover, a cusp is observed in the magnetoresistance which we attribute to weak antilocalization; hinting at a contribution of the surface states to the overall transport, despite the high bulk conductivity.

[1] Hsieh, T., et al. Nat Commun 3, 982 (2012)

[2] Volobuev V.V., et al. Adv. Mat. 23, 3, 1604185 (2016)

[3] Safdar, M., Wang, Q., et al. Nano Lett. 15, 2485-2490 (2015)

[4] Xiao, J., Yan, B. Nat Rev Phys 3, 283–297 (2021).

[5] Jung, J. Schellingerhout, A.G. ArXiv:2209.09758v1 (2022)