Dragan Mihailovich (Special Seminar)

Date/Time
Date(s) - Feb 12 2014
10:30 AM - 11:30 AM

Location
Room 335, McCullough Building

Category(ies)


Prof. Dr. Dragan D. Mihailovic

Chief scientist at “Jozef Stefan” Institute, and Professor at the University of Ljubljana, Slovenia

 

 

 Trajectories through phase transitions in time: From oscillating order to topologically protected hidden states

 

 

 New techniques in time-resolved optical spectroscopy allow us to investigate phase transitions under controlled, yet highly non-ergodic conditions. The measurement of the temporal evolution of not only single particle and collective excitations, but also topological excitations through the transition lead to a new insight into the emergence of functional properties under non-equilibrium conditions.  The experiments on well-known rare earth tellurides and transition metal chalcogenides which I will discuss reveal some unexpected phenomena. Femtosecond coherent oscillations of the order parameter and the subsequent creation and annihilation of topological defects lead to the emission of detectable Higgs-like amplitude waves. Most remarkably, switching to a stable, topologically protected state can occur under specific conditions, opening a route to the creation of hidden states.  Such switching at unprecedented speed between charge ordered states indicates a potential for ultrafast non-volatile memory technology.

 

 R. Yusupov et al Nat. Phys. 6, 681 (2010)

 

L. Stojchevska et al., cond-mat (2014)