Quantum Cafe: Nadya Mason

Date & Time

Title: Surface State Magnetoresistance in 3D Topological Insulators

Abstract: Topological insulators (TIs) have a variety of unique transport properties, including strong spin-orbit coupling and symmetry-protected spin-momentum locked surface states. These properties have driven significant interest in understanding the science and device potential of systems that combine TIs with magnetism. In this talk, I will first describe how a parallel magnetic field through a TI wire leads to Aharonov-Bohm oscillations, indicative of ballistic surface transport. I will then discuss how proximity magnetization— i.e., placing a layer of magnetic material in direct contact with the TI—can be used to control the surface state symmetry, and thus the transport properties. In particular, for the TI Bi2Se3 on the magnetic insulator YIG, we experimentally observe a new MR effect, that is identified as anisotropic magnetoresistance consistent with a magnetized surface state. The result is consistent with magnetic anisotropy out of the sample plane opening an energy gap between the surface states and provides insights into the fundamental mechanisms of magnetic proximity and interface interactions in topological systems.

For Zoom details please contact Mary Kate Hennelly at mhennelly@flatironinstitute.org

About the Speaker

Professor Nadya Mason received her bachelor’s degree in physics from Harvard University in 1995 and received her doctorate in physics in 2001 from Stanford University, working in the group of Aharon Kapitulnik. Her thesis research was on phase transitions in two-dimensional superconductors.

Prior to joining the physics faculty at Illinois, Professor Mason was a Junior Fellow in the Society of Fellows at Harvard University, where she collaborated with Professors Charles Marcus and Michael Tinkham on projects related to both carbon nanotubes and nanostructured superconductor

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