Physics Dept - MtSE Joint Seminar

April 2nd, Monday

The Birth of New Particles from Structure and Disorder at a Topological Insulator Surface

Prof. L. Andrew Wray

Dept. of Physics, NYU

(Condensed Matter/Materials Physics, Host: Ken Ahn)

Time: 11:45am-12:45pm with 11:30am tea time

Room: ECE 202

Since the discovery of the first materials with intrinsic topological electronic order one decade ago, there has been an ongoing cascade of progress in the identification of new particles, states of matter, and physical phenomena enabled by topological principles. Topologically ordered materials exhibit a phenomenon called “bulk-boundary correspondence”, whereby the quantum topology causes new exotic electronic states (termed quasiparticles) to manifest wherever the electronic structure is disrupted, such as at material interfaces, structural defects, or superconducting vortices. These exotic quasiparticles set new ground rules for the behavior of physical matter, and are at the heart of some of the most exciting recent proposals for next generation technologies. I will talk about some of my group’s explorations into the interplay between quantum topology and the nanoscale crystalline structure, based on experimental techniques that resolve single electrons (ARPES, STM). These studies have revealed new species of electronic state, including: interlinked light-like quasiparticles; quasiparticles that move along atomic step edges as if they were perfect wires; and a state behaves like a free particle but lacks short-range translational symmetry, and thus breaks the most basic rule upon which quasiparticles are usually mathematically defined.