COSAM » COSAM Faculty » Physics » Ryan Comes

Ryan Comes
Assistant Professor

Research Areas: Experimental Condensed Matter Physics

Office: 231 Allison Laboratory

206 Allison Laboratories
Auburn, AL 36849-5319

Phone: (334) 844-3641



University of Virginia, Ph.D. Engineering Physics
Carnegie Mellon University, B.S. Physics/Electrical and Computer Engineering

Professional Employment

Auburn University, Department of Physics, Assistant Professor
Pacific Northwest National Laboratory, Linus Pauling Distinguished Postdoctoral Fellow

Honors and Awards

National Defense Science and Engineering Graduate Fellowship
Materials Research Society Graduate Student Silver Award
University of Virginia Engineering Research Symposium, First Place
University of Virginia School of Engineering and Applied Sciences Dean's Fellowship
National Science Foundation Graduate Research Fellowship, Honorable Mention

Professional Activities

Peer Reviewer: Nano Letters, ACS Nano, Advanced Functional Materials, Physical Review B, Nanoscale, Applied Physics Letters, Journal of Applied Physics, APL Materials, and others
Member: American Physical Society, Materials Research Society, American Vacuum Society, American Ceramics Society
Member: Phi Beta Kappa, Tau Beta Pi, Eta Kappa Nu
American Physical Society March Meeting 2017: Focus Session organizer, Complex Oxide Interfaces and Heterostructures

Research and Teaching Interests

Our work on the growth of complex oxide thin films, mulitlayers, superlattices and nanostructures for electronic and energy applications. These applications include next-generation memory and logic devices, quantum computation, catalysis and photovoltaics. Materials such as SrTiO3 and BaTiO3 have excellent properties for these applications, but have a bandgap that is too large to absorb light in the visible regime. Through a variety of doping techniques and epitaxial growth techniques, we are looking at ways to reduce the bandgap in the materials.

We use molecular beam epitaxy to grow extremely high quality epitaxial films. We employ in situ x-ray photoelectron spectroscopy (XPS) to measure the film stoichiometry to ensure that we are making ideal films. Descriptions of these systems that are currently being designed can be found here. Our XPS capabilities also allow us to measure valence band structureband alignment across interfacesbuilt-in electric fields and the oxidation state of the constituent ions in the lattice. This allows us to understand the properties of our materials as they are grown and allows us to quickly generate high impact results.

Selected Publications

  1. Ryan B. Comes, Steven R. Spurgeon, Mark H. Engelhard, Despoina M. Kepaptsoglou, Tiffany C. Kaspar, Quentin M. Ramasse, Peter V. Sushko, and Scott A. Chambers. “Probing the Origin of Interfacial Carriers in SrTiO3-LaCrO3Superlattices,” Chemistry of Materials29, 1147–1155, Feb 2017. DOI: 10.1021/acs.chemmater.6b04329
  2. Ryan B. Comes and Scott A. Chambers. “Interface structure, band alignment and built-in potentials at LaFeO3/n-SrTiO3 heterojunctions,” Physical Review Letters117, 226802, Nov 2016. DOI: 10.1103/PhysRevLett.117.226802
  3. Peng Xu, Yilikal Ayino, Christopher Cheng, Vlad Pribiag, Ryan B. Comes, Peter V. Sushko, Scott A. Chambers and Bharat Jalan. “Understanding and controlling charge density in the two-dimensional electron gas at a polar/non-polar oxide interface,” Physical Review Letters117, 106803, Sep 2016. DOI: 10.1103/PhysRevLett.117.106803
  4. Ryan B. Comes, Steven R. Spurgeon, Steve M. Heald, Despoina M. Kepaptsoglou, Lewys Jones, Phuong Vu Ong, Mark E. Bowden, Quentin M. Ramasse, Peter V. Sushko, and Scott A. Chambers. “Interface-induced Polarization in SrTiO3-LaCrO3 Superlattices,” Advanced Materials Interfaces3(10), 1500779, May 2016. DOI: 10.1002/admi.201500779
  5. Ryan B. Comes, Scott A. Chambers, Andrew Xu, and Bharat Jalan. “Band alignment of epitaxial SrTiO3 thin films with (LaAlO3)0.3-(Sr2AlTaO6)0.7 (001),” Applied Physics Letters107, 131601, Sep 2015. DOI: 10.1063/1.4932063.
  6. Ryan B. Comes, Sergey Y. Smolin, Tiffany C. Kaspar, Ran Gao, Brent A. Apgar, Lane W. Martin, Mark E. Bowden, Jason Baxter, and Scott A. Chambers. “Visible light carrier generation in co-doped epitaxial titanate films,” Applied Physics Letters106, 092901, Mar 2015. DOI: 10.1063/1.4913930
  7. Ryan B. Comes, Peter V. Sushko, Steve M. Heald, Robert J. Colby, Mark E. Bowden, and Scott A. Chambers. "Band-Gap Reduction and Dopant Behavior in La, Cr Co-doped SrTiO3 Thin Films," Chemistry of Materials26, 7073-7082, Dec 2014. DOI: 10.1021/cm503541u
  8. Ryan Comes, Hongxue Liu, Mikhail Khokhlov, Richard Kasica, Jiwei Lu and Stuart A. Wolf. "Directed Self-Assembly of Epitaxial CoFe2O4-BiFeO3 Nanocomposites," Nano Letters12 (5), 2367-2373, May 2012. DOI: 10.1021/nl3003396

Last updated: 04/04/2017