Ryan Comes
Department of Physics
Thomas and Jean Walter Associate Professor

Research Areas: Experimental Condensed Matter Physics

Office: Leach Science Center 3113

Address: 380 Duncan Drive
Auburn, AL 36849

Phone: (334) 844-3641

Email: ryan.comes@auburn.edu


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

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

Honors and Awards
National Science Foundation CAREER Award
Air Force Young Investigator Award
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: Nature Materials, Science Advances, Nano Letters, ACS Nano, Advanced Functional Materials, Physical Review Letters, Physical Review B, Applied Physics Letters, and others
Grant Reviewer: National Science Foundation, Department of Energy, Air Force Office of Scientific Research, 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 and 2019: Focus Session organizer, Complex Oxide Interfaces and Heterostructures
American Ceramics Society, Electronic Materials and Applications Conference: Symposium Organizer 2018-2020

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. Suresh Thapa, Sydney R. Provence, Devin Jessup, Jason Lapano, Matthew Brahlek, Jerzy T. Sadowski, Petra Reinke, Wencan Jin, and Ryan B. Comes. “Correlating surface stoichiometry and termination in SrTiO3 films grown by hybrid molecular beam epitaxy,” Journal of Vacuum Science and Technology A39, 053203, Sep 2021. DOI: 10.1116/6.0001159
  2. Suresh Thapa+, Rajendra Paudel+, Miles Blanchet+, Patrick Gemperline+ and Ryan B. Comes. “Probing surfaces and interfaces in complex oxide films via in situ X-ray photoelectron spectroscopy,” Journal of Materials Research, 36, 26-51, Jan 2021. DOI: 10.1557/s43578-020-00070-9 
  3. Miles D. Blanchet, Jonathan J. Heath, Tiffany C. Kaspar, Bethany E. Matthews, Steven R. Spurgeon, Mark E. Bowden, Steve M. Heald, Tamara Issacs-Smith, Marcelo A. Kuroda, and Ryan B. Comes. “Electronic and Structural Properties of Single-crystal Jahn-Teller Active Co1+xMn2-xO4 Thin Films,” Journal of Physics: Condensed Matter, 33, 124002, Jan 2021. DOI: 10.1088/1361-648X/abd573
  4. Sydney R. Provence, Suresh Thapa, Rajendra Paudel, Tristan Truttmann, Abhinav Prakash, Bharat Jalan, and Ryan B. Comes. “Machine Learning Analysis of Perovskite Oxides Grown by Molecular Beam Epitaxy,” Physical Review Materials4, 083807, Aug 2020. DOI: 10.1103/PhysRevMaterials.4.083807
  5. 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
  6. 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
  7. 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
  8. 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
  9. 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
  10. 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: 08/25/2022