Elsa Abreu - Preliminary Oral Examination

When: January 19, 2011 (Wed), 03:00PM to 04:00PM (add to my calendar)
Location: PRB 365

This event is part of the Preliminary Oral Exam.

Title: Ultrafast spectroscopy of strongly correlated systems – VO2 and Sr14Cu24O41

Examining Committee: Richard Averitt, Shyamsunder Erramilli,
Claudio Chamon, Robert Carey

Abstract:

We use ultrafast spectroscopy in the THz and optical regimes to study the static and dynamic properties of systems with strong electron correlations. In particular, we are interested in understanding the nature of the metal-insulator transition (MIT) in VO2. We have observed a large strain induced anisotropy in both the conductivity and the transition temperature of strained VO2 thin films, probed by THz time domain spectroscopy (Fig.1). These results demonstrate the possibility of strain engineering the properties of VO2, while shedding a new light onto a long lasting controversy regarding the structural vs. correlation driven nature of the MIT in this material. We are also interested in probing the dynamics of Sr14Cu24O41, a quasi-1D compound which exhibits superconductivity when appropriately doped with Ca. Sr14Cu24O41 consists of stacked layers of alternating 1D CuO2 chains and quasi-1D Cu2O3 ladders. Preliminary results reveal contributions from both chains and ladders dynamics in the temperature dependent THz response of the material.

Best wishes to Elsa!!!