Dissertation Committee Chair: Dr. James Williams
Committee:
Dr. Gretchen Campbell
Dr. Alicia J. Kollar
Dr. Frederick C. Wellstood
Dr. Ichiro Takeuchi (Dean's Rep)
Abstract: Studying topological states of matter offers potential routes to novel excitations with properties beyond that of simple electrons. While the range of materials and techniques for studying topological systems is constantly expanding, only a handful of systems have been thoroughly studied. Topological crystalline insulators (TCI) and the rich states present in ZrTe5 offer alternative routes to studying topological states of matter with surface states of distinct character to those in more common 3d topological insulators.
First, we report on the fabrication of Josephson junctions using MBE-grown candidate TCI material — Pb-doped SnTe — as weak links. We then perform transport characterization measurements on these devices including the effects of DC, RF, and magnetic field biases. Finally, we model these results using a skewed current phase relationship using the resistively shunted josephson junction model.
In the second section, we present the fabrication of devices from mechanically exfoliated ZrTe5 nanowires. After fabrication, we perform magnetoconductance measurements at various temperatures for these devices. We then use existing models for weak antilocalization and universal conductance fluctuations for a quasi-1D system in order to extract a coherence length for this system.
https://umd.zoom.us/j/8011470585?pwd=S2tpeUpiWkdTTjAyRXVENVN3R2RsQT09