Date of Award
8-1-2018
Degree Name
Master of Science
Department
Physics
First Advisor
Mazumdar, Dipanjan
Abstract
Time-Reversal Symmetry (TRS) is a hallmark of Topological Insulator (TI) systems. TRS in conjuction with the strong Spin-Orbit Coupling (SOC) present in Bismuth Selenide is responsible for the uniquely robust surface states shown in this material. Breaking TRS in these systems in order to achieve gapped surface states requires the presence of a magnetic field throughout the material. We achieve this effect by doping the system with 4f elements whereby the magnetic field is provided by the local magnetic moments of the dopants manifesting ferromagnetic behavior. Through this spontaneous gap opening in the surface states in is expected that the Quantum Anomalous Hall Effect is present in the system. This thesis provides experimental evidence of good candidate materials for measuring the Quantum Anomalous Hall Effect. By combining X-ray Diffraction to ensure good crystal growth, Angle-resolved Photoemission Spectroscopy probe to the evolution of the bandstructure as an effect of doping and Density Functional Theory to support the experimental data it is shown in this work that Samarium doped Bismuth Selenide is a prime candidate for displaying the Quantum Anomalous Hall Effect.
Access
This thesis is Open Access and may be downloaded by anyone.