Two-Dimensional Weak Antilocalization Signatures Due to Quantum Coherent Transport in Nanocrystalline SnTe

Abstract

Nanostructured topological crystalline insulators (TCIs) in the presence of exotic surface states with spin momentum locking reported in individual nanostructures are predicted to hold a great promise for spintronics and quantum computing applications. However, practical application demands a strategy with large-scale production and integration for device applications. In this work, we demonstrate through prominent signatures of weak antilocalization (WAL), arising predominantly from destructive quantum interference on robust surface states, that a correlated TCI phase is possible in the nanobulk assembly of carefully nanostructured quasi-two-dimensional SnTe (edge-to-edge length ∼ 382 nm) synthesized by a simple, rapid, and scalable microwave-assisted solvothermal method. Hikami–Larkin–Nagaoka analysis (T –0.71), as well as the temperature dependence of resistivity, illustrates an interplay of both conductions from 2D channels and 3D EEI effects as the precursor for the observed WAL at low temperatures (2–6 K). Interestingly, the enhanced thermoelectric power of the sample of ∼45 μV/K, with a p-type carrier concentration of ∼1018/cm3 at 300 K, makes this SnTe nanocrystalline assembly more attractive as a multifunctional material for large-scale technological applications.

Complex coincidence of superconducting and inverse proximity in quasi 2D nanostructured SnTe

“…The CL versus temperature relation corresponds to a power law, indicating a value of n = 0.70, which indeed shows the presence of 3D EEI in our sample [29][30][31]. The right axis of figure 2(b) shows the difference in the CL (∆L Φ ) of SnTe with indium contacts compared with SnTe/Ag [24], which shows an overall reduction in CL and a prominent jump at 4 K of about 57% that signifies the suppression of WAL by dephasing due to the formation of superconducting interfaces around these temperatures.…”

“…Inverse proximity (IP) in SC/TCI interfaces is reported to be a promising situation to search for the signature of such a triplet state. We unambiguously established the presence of a 2D surface state signature in a nanostructured TI [23] and TCI [24] in our earlier work.…”

“…The resistivity and magnetoresistance of nanostructured SnTe with silver contacts were described in detail in our previous study, where only WAL signatures emerged owing to topological quantum interference [24]. In this section we show that when indium is used as an electrode above the same sample, a plethora of behaviors can be observed at low temperatures.…”

“…The CL of SC calculated in D3 and the CL of TCI using silver contacts as published in our earlier work [24] are plotted as a function of temperature in figure 5(c) for the superconducting proximity region.…”

“…A schematic diagram of the synthesis procedure and basic characterization such as x-ray diffraction, atomic force microscopy, field-emission scanning electron microscopy and energy-dispersive -ray spectroscopy analysis were given in our earlier report [24]. The resistivity and resistance versus magnetic field measurements were performed in a Quantum Design 14 T Physical Property Measurement System (PPMS).…”