Electronic Transport in PbSnTe Weak Link Josephson Junctions and ZrTe5Nanowires

Abstract

ABSTRACTStudying topological states of matter offers potential routes to novel excitations withproperties beyond those of simple electrons. While the range of materials and tech-niques for studying topological systems is still expanding, only a handful of systemshave been thoroughly studied. Topological crystalline insulators (TCI) and the richstates present in ZrTe5offer alternative routes to studying topological states of matterwith surface states that have a distinct character compared to those in more common3D topological insulators.First, I report on the fabrication of Josephson junctions using a MBE-grown can-didate TCI material — Pb-doped SnTe — as weak links. We then perform transportcharacterization measurements on these devices including the effects of DC, RF, andmagnetic field biases. I compare my results to a model that uses a skewed current-phase relationship and the resistively shunted Josephson junction model. I find goodqualitative agreement between experimental data and numerically calculated data.In the second section, I describe the fabrication of devices made from mechanicallyexfoliated ZrTe5nanowires. I then present results from magnetoconductance measure-ments from 50 mK to 1 K on these devices. Finally I apply existing models for weakantilocalization and universal conductance fluctuations for a quasi-1D system in orderto extract a coherence length up to 1.5μm at 50 mK and 700 nm at 1 K