Topological insulator

This is a very intersting topic, in many ways. Topological insulator is a new quantum phase of matter, recently proposed theoretically. It is required to be a bulk insulator and a topologically protected surface metal. ARPES data have been crucial in ascertaining the topological insulator nature of various materials, now accepted as topological insulators, even though the bulk crystal of many of these materials has remnant charge carriers and thus is not an insulator. The protected surface state has a strong similarity to the electronic structure of graphene, whose “Dirac-cone” electronic structure was measured by ARPES for the first time, in an experiment led by G.-H. Gweon.

Here at UCSC, we are studying these materials from two different perspectives. First, we are studying interaction effects in topological insulators. Second, the surface metallic state in topological insulator materials seems a very good reference to compare with anomalous line shapes in quasi-two-dimensional and quasi-one-dimenasional cuprates that our group study.

Students

• Ahram Kim (grad student) and Eric Reichwein (undergrad student) are woking on this project.
• A summer intern from high school, Richelle Smith, helped with this project during the summer of 2012.
• Gregory Kaminsky (grad student) has been helpful in discussions of topological insulator.