[The University of Texas at Austin: What starts here changes the world]

Physics Event · · ·

Physics Colloquium: Nuh Gedik, MIT

Date and Time: Wednesday, January 23, 2013 at 4:15 PM (CST)
Location: RLM 4.102

Physics Colloquium

Nuh Gedik, MIT

"Shining Light on Topological Insulators"

4:15pm, The John A. Wheeler Lecture Hall (RLM 4.102)

Coffee and cookies will be served at 4:00pm in RLM 4.102


Topological insulators (TIs) are novel materials that do not conduct electricity in their bulk yet possess exceptional conducting electronic states on their surface. These surface electrons have a number of highly unusual characteristics: (i) they behave like massless relativistic particles with a linear energy-momentum dispersion relation (ii) their spin is locked perpendicular to their momentum and (iii) this state is robust against moderate disorder. Understanding and characterizing unique properties of these materials can lead to novel applications such as current induced magnetization or extremely robust quantum memory bits. In this talk, I will give an overview of this field and discuss recent experiments in which we used ultrafast laser pulses to probe the fascinating properties of these materials. In particular, I will present measurements in which we simultaneously mapped all three components of spin over the entire energy momentum phase space by using circularly polarized ultrafast laser pulses to perform novel angle-resolved photoelectron spectroscopy. I will show that an idealized spin-momentum locking is only present within a small energy window about the Dirac point, beyond which strong textural deformations occur. I will also describe our experiments in which we directly visualized the coupling of topological surface electrons to other excitations by recording 3D movies of electronic band structure after photoexcitation by an ultrashort laser pulse.

September 23 14:00 RLM 7.104
Revisiting soliton contributions to perturbative amplitudes
September 23 17:00 RLM 7.104
The Alice Experiment at the LHC -- A Little Big Bang!
September 24 12:00 RLM 8.136
Topics of interest to physicists and mathematicians
September 24 16:15 The John A. Wheeler Lecture Hall (RLM 4.102)
The Question of Mass in Newton's Law of Gravity
September 25 12:30 RLM 9.222
Members of the Theory Group discuss their work
September 25 12:30 RLM 11.204
Nanoscale magnetic imaging at ambient conditions using a scanning nitrogen-vacancy center in diamond
September 26 12:00 WAG 316
An Alternative Agenda for Philosophy of Science
September 26 16:00 RLM 5.104
Topological phases in transition metal oxides
September 29 13:00 RLM 11.204
Rheology of suspensions and emulsions
September 30 09:30 RLM 13.202
Microwave Impedance Microscope Study of Two Dimensional Material Electrical Properties
September 30 17:00 RLM 7.104
Understanding the Higgs Boson with the Large Hadron Collider!
October 1 16:15 The John A. Wheeler Lecture Hall (RLM 4.102)
title tba
October 1 16:15 The John A. Wheeler Lecture Hall (RLM 4.102)
Excited Masses: Adventures in Public Outreach
October 8 16:15 The John A. Wheeler Lecture Hall (RLM 4.102)
title tba