PHAS Colloquia

Ultrafast phenomena in quantum materials

by Ioannis Chatzakis (Texas Tech University)

Tuesday, 8 September 2020 from to (America/Chicago)
Speaker: Dr. Ioannis Chatzakis (Physics & Astronomy, Texas Tech University)

Title: Ultrafast phenomena in quantum materials

Abstract: Novel materials with nanoscale functionality continue to gain prominence in applications ranging from electronics to photonics and to alternative energy generation systems. Critical to efficiently developing these systems is the understanding of the fundamental processes related to the dynamics of charge carriers, phonons, and other excitations (i.e. excitons, polaritons). Understanding the principles that govern these excitations will enable the fabrication of optoelectronic and photonic devices with novel and enhanced functionalities. While significant studies of nanomaterials, optical, and electrical transport properties are often made, identifying the mechanisms and timescales governing the interactions between electrons, phonons, and other excitations can be extremely challenging. In this talk, I will focus on electron-phonon interactions through which electrons lose their energy and become thermally equilibrated, and the phonon-phonon scattering processes responsible for energy release into the environment as heat. In addition, I will discuss the recombination mechanism of the photo-generated charge carriers, and present the main capabilities of ultrafast spectroscopy as an experimental method for the study of these mechanisms.

About the speaker: Ioannis Chatzakis received the American Society for Engineering Education (ASEE) fellowship and is currently residing as postdoctoral researcher at the Naval Research Laboratory (NRL) in Washington, DC. He received his Ph.D. in Physics from Kansas State University in Dec. 2009, while his research was carried out at Columbia University under Prof. T. F. Heinz, working on the investigation of the optical and electronic properties of carbonic materials. He holds an M.Sc. degree in Physical Chemistry (Applied Molecular Spectroscopy), and a B.Sc. degree in Electrical Engineering. Before starting working at NRL, he trained as postdoctoral researcher at Iowa State University/Ames Laboratory, Stanford University, and University of Southern California (USC). Dr. Chatzakis was awarded the USC Provost’s Postdoctoral Scholar Research Grant, one of seven among 71 submissions, which supported independent research. While at USC he worked on terahertz devices based on artificial multilayer graphene. He is a member of the American Physical Society, Materials Research Society, and Optical Society of America. He serves the community as a reviewer in several scientific journals and review panels.


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Organised by Stefan Estreicher/CMP