Nitin Samarth, George A. and Margaret M. Downsbrough Department Head, Department of Physics, Penn State University

Title:  "Topological Insulators: From Exotic Quantum States to Spintronics"   (video)

Abstract: The surface electrons of 3D topological insulators are known to possess a helical Dirac spin texture [1] that can be exploited for studying exotic quantum states (such as condensed matter versions of Majorana fermions, axions and supersymmetry) to pragmatic spintronic devices for information technology. I will provide a perspective on this field, with examples of how we create novel phases of matter by interfacing a topological insulator with magnetism [2] and superconductivity [3].  I will also discuss the recent emergence of "topological spintronics," demonstrating how the spin texture of a topological insulator leads to striking phenomena useful for devices, including the generation of a spin-orbit torque of record efficiency at room temperature [4].

1. M. Neupane, A. Richardella et al., Nature Communications 5, 3841 (2014).
2. S.-Y. Xu et al., Nature Physics 8, 616 (2012).
3. S.-Y. Xu et al., (submitted).
4. A. Mellnik, J. S. Lee, A. Richardella et al., Nature 511, 449 (2014).