This special Physics department colloquium is scheduled for Thursday 7/9/15 at 3:00 pm in in the Kenwood Interdisciplinary Research Complex (KIRC) Room KEN 1140. Tea, coffee, and cookies will be available in KEN 3118 (third floor kitchenette located next to the elevators) at 2:30 PM. Anyone is welcome.

Tunneling Experiments with Dirac Electrons in Graphene Heterojunctions
Shivani Rajput, PhD Candidate/UWM Dept. of Physics

Sparked by the isolation of graphene in 2004, recent research has uncovered a new class of materials with their low-energy excitations behaving a massless Dirac particles rather than fermions obeying the canonical Schrödinger equation. In this talk, using graphene as an example, I will first briefly give a sense of why Dirac materials have generated such excitement in condensed matter physics. I will then present my research on the understanding of graphene heterojunctions at the atomic scale using scanning tunneling microscopy/spectroscopy. In the first case, I will show how charge carriers in graphene can be controlled by substrate polarization in graphene-SiC heterojunctions. In the 2nd case, I will present the atomic resolution imaging of graphene ripples and other intrinsic spatial inhomogeneities that affect the Schottky barrier at graphene-semiconductor junctions. Lastly, I will show the transfer of giant spin-orbit coupling in graphene through proximity to a three-dimensional-topological insulator Bi2Se3, making possible the observation of the quantum spin Hall effect at room temperature.