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About Me

Family with Cornell signDerek in front of Duffield HallDerek with kids

 

What I do

I am the scientific computational research associate, managing modeling and theory at the Cornell Nanoscale Facility at Cornell University in Ithaca, New York. The CNF is an user facility where academic, industrial, and government researchers from across the country can come to take advantage of our unique fabrication and computational capabilities.  The CNF is also part of the National Nanotechnology Infrastructure Network which provides user facilities for researchers at academic institutions across the country.  My work involves providing a range of modeling capabilities for nanoscale research, while at the same time working to expand the capabilities through research, code developments, and collaborations.  Scientific modeling and simulation on the cluster was highlighted in the spring 2006 CNF newsletter, the Nanometer. I have also organized and hosted three computational workshops looking at a variety of nanoscale simulation techniques from nanophotonics, microfluidics, first principle approaches to nanoscience and geology. I have collaborated with environmental scientists, physicists, chemists, material scientists, electrical and mechanical engineers. If you have an idea that needs computational modeling, come see me! If you would like to learn more about becoming a user at the CNF or if you have questions about my research, please send me email at stewart@cnf.cornell.edu.

 

San Francisco

Postdoc Years in Sunny California

Nanotubes, Green's Functions, and More

Nanotube

Before coming to Cornell, I did a post-doctoral fellowship at Sandia National Laboratory in Livermore, California.  During that time, I worked with non-equilibrium Green’s function approaches to model systems ranging from magnetic tunnel junctions to nanotube photodetectors.  You can find a description of some of the work at this project page.  I also created the images for the nanotube devices on the page using the ray tracer POVRAY.

Nanotube
Artistic rendering of illuminated nanotube p-n junction using POVRAY (Copyright Derek Stewart 2005)

 

Associated Papers with Sandia National Lab:

F. Léonard and D. A. Stewart, “Properties of short channel ballistic carbon nanotube transistors with ohmic contacts”, Nanotechnology, 17, 4699 (2006). (ArXiv Version)

J. Velev, K. D. Belashchenko, D. A. Stewart, M. van Schilfgaarde, S. S. Jaswal, and E. Y. Tsymbal, “Negative spin polarization and large tunneling magnetoresistance in epitaxial Co/SrTiO 3/Co magnetic tunnel junctions”, Physical Review Letters, 95, 216601, (2005). (Digital Commons version)

S. Faleev, F. Léonard, D. A. Stewart, and M. van Schilfgaarde, “Ab-initio TB-LMTO method for non-equilibrium electron transport in nanosystems”, Physical Review B, 71, 195422, (2005). (Local copy)

D. A. Stewart and F. Léonard, “Energy Conversion Efficiency in Nanotube Optoelectronics”, Nano Letters, 5, No. 2, 219, (2005).

D. A. Stewart and F. Léonard, “Photocurrents in Nanotube Junctions”, Physical Review Letters, 93, 107401, (2004). (Local copy)

K. D. Belashchenko, E. Y. Tsymbal, M. van Schilfgaarde, D. A. Stewart, I. I. Oleynik, and S. Jaswal, “Spin-dependent tunneling from clean and oxidized Co surfaces”, Journal of Magnetism and Magnetic Materials, 272-276, 1954, (2004). 

K. D. Belashchenko, E. Y. Tsymbal, M. van Schilfgaarde, D. A. Stewart, I. I. Oleynik, and S. Jaswal, “Effect of Interface Bonding on Spin-Dependent Tunneling from oxidized Co Surfaces”, Physical Review B, 69, 174408, (2004). (ArXiv Version)

UVA Thomas Jefferson

My Graduate Years

University of Virginia and Oak Ridge National Lab

Oak Ridge National Lab

 

Masters Work

I obtained my masters of science in 1998 from the University of Virginia in Charlottesville. There, I worked in the microscale heat transfer lab of Dr. Pamela Norris focusing on the surface and size effect on the thermal conductivity of microscale metallic structures.

D. A. Stewart, "Surface and Size Effects on the Thermal Conductivity of Microscale Metallic Structures," Masters of Science Thesis, University of Virginia, (1998).

Ph.D. Work

I stayed at the University of Virginia for my doctorate, but continued my research through the ORISE program at the Oak Ridge National Lab. There, I worked with the materials theory group under the direction of Dr. Bill Butler. Dr. Bill Butler is now the director of the Center for Materials for Information Technology at the University of Alabama.

D. A. Stewart, "Effect of Diffusive Scattering on Giant Magnetoresistance in Magnetic Multilayers", Ph. D. Dissertation, University of Virginia, (2001).

 

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