Author: Amirhossein Khalaj Hedayati

Seminar on High Resolution Transmission Electron Microscopy: The Debye-Waller factor and the thermodynamic stability of graphene

Amirhossein Khalaj Hedayati / / Instrument Status

Thursday February 13 2014, 2:00 pm

McDonnell Douglas Engineering Auditorium

 

 

The Debye-Waller factor and the thermodynamic stability of graphene

Dr.  Matthew Mecklenburg

Center for Electron Microscopy and Microanalysis, USC

Please RSVP here!

Abstract:   Why are two dimensional materials stable and how can we use electron microscopy to understand their stability?   2D crystals are impossible, according to some interpretations of work by Landau and Peierls. Thus, suspended graphene’s evident stability poses fundamental questions about long-range order in two-dimensional crystals.   With information gathered from a variety of electron microscopy techniques that include aberration corrected imaging and diffraction we are able to understand the stability of graphene and other two dimensional materials.  The good agreement between our ab initio theory and experiment indicates that ripples in the third dimension are not necessary to resolve graphene’s alleged stability paradox.

 

If you have any questions please contact Amir at: akhalajh@uci.edu

 

Bio:  Dr. Mecklenburg is the senior staff scientist at the University of Southern California’s Center for Electron Microscopy and Microanalysis.  He is an expert in electron microscopy, in particular in situ characterization of materials using heating and electrical biasing techniques.   He received his Ph. D. in physics at UCLA working with Prof. Regan, whose research is focused on the in situ microscopy of microelectronic devices and fluid cells.  After graduating he worked for an FFRDC, The Aerospace Corporation, where he received an internal grant to develop new techniques for in situ temperature measurements, and where he worked with SiMPore, Inc. to develop a new type of sample support to allow electrical biasing of samples prepared with a focused ion beam.  At The Aerospace Corporation he also worked extensively on projects directed by the Air Force Space and Missile Command and the National Reconnaissance Office related to the development and testing of microelectronic devices for space based applications.  Currently he teaches the graduate level class in electron microscopy at the University of Southern California and is developing new in situ microscopy techniques to better understand nano-scale thermodynamics.