Quantum transport in patterned SnTe

SnTe belongs to the class of topological crystalline insulators (TCI), which have non-trivial conducting states where the mirror symmetry is broken at surfaces and edges. To study this behavior, we synthesize SnTe films using molecular beam epitaxy (MBE). The films have high surface area and edge length to volume ratios, which is achieved by growing films patterned with a semi-regular array of square vacancies (200 nm x 200 nm). To measure the effect of these vacancies on electronic conduction, we compare quantum transport measurements on both patterned and unpatterned films. The magnetoconductivity results are fitted with the Hikami-Larkin-Nagaoka (HLN) equation and reveal a mixture of weak localization and weak antilocalization (WL/WAL), which indicates conduction in spin-momentum locked electronic states. The stronger WAL effect at higher temperatures (5K to 10K) in the patterned films shows the suppression of bulk conduction by the presence of square vacancies, and the limited coherence length at low temperatures (2K to 5K) is consistent with scattering at the vacancy boundaries.