Dr. Comes Co-Organizing International Workshop on Oxide Electronics

Dr. Comes is co-organizing the 28th International Workshop on Oxide Electronics with Profs. Menka Jain (University of Connecticut), Divine Kumah (North Carolina State University), and Charles Ahn (Yale University). The IWOE will be held in Portland, Maine from October 2nd to October 5th at the Westin Portland Harborview.

“The International Workshop on Oxide Electronics series has become an important venue to discuss recent advances and emerging trends in this developing field. The aim of the workshop is to provide an interdisciplinary forum for researchers – theorists as well as experimentalists – on understanding the fundamental electronic and structural properties and also on the design, synthesis, processing, characterization, and applications of (epitaxial) functional oxide materials. Results of critical scientific importance as well as studies revealing the technological potential of functional oxide thin films to create devices with enhanced performance will be showcased.”

Abstract submission is now open on the website and are due June 15th. We look forward to seeing you in Maine!

Congratulations to Miles Blanchet and Suresh Thapa!

Suresh and Miles are the first two FINO Lab Ph.D. graduates! Both defended their dissertations over the last week and did a great job.

Miles’dissertation is entitled “Synthesis and Characterization of Mn-based Spinels Grown by Molecular Beam Epitaxy.” He has written two first author papers and has another in preparation on Mn spinels for water-splitting catalysis applications on our NSF project with Prof. Byron Farnum’s group. He was the first Ph.D. student to join the group and helped build the group’s MBE and XPS. He’ll be moving on to an industrial job over the summer that is being finalized soon. Congrats Miles!

Suresh did the first in situ studies on films grown by hybrid MBE, including SrTiO3 and SrNbO3. His thesis is entitled “Surface and Interfacial Studies of Perovskite Oxides Grown by Hybrid Molecular Beam Epitaxy” and was supported by our AFOSR grant. He has written a first author paper, has another in review, and one more in preparation. Suresh will move on to a job with Intel in Hillsboro, OR over the summer. Way to go Suresh!

Paper on MnFe2O4 Oxygen Reduction Reaction Catalysts Published in ACS Catalysis

Cyclic voltammetry of MnFe2O4 and Fe3O4 samples

Our collaborative paper with Prof. Byron Farnum’s group in the Department of Chemistry has been published in ACS Catalysis. In this work, Miles Blanchet from FINO Lab grew a series of MnFe2O4 and Fe3O4 samples by MBE on Nb-doped SrTiO3 and performed in situ XPS measurements. Alex Bredar from Prof. Farnum’s group performed cyclic voltammetry studies to examine the use of the materials for the oxygen reduction reaction (ORR). Mn-based spinels have generated significant interest for their use in ORR and this work is the first to examine epitaxial films for ORR to attempt to explain the role that Mn plays in the catalysis. The work was funded by NSF through our collaborative grant.

Collaborative Paper on (La,Sr)2CuO4 Surface Reconstructions Published in Journal of Vacuum Science and Technology A

K-means clustering of RHEED images during growth and annealing of (La,Sr)2CuO4 film

Our collaborative paper with Dr. Eren Suyolcu of Cornell University and Prof. Gennady Logvenov of Max Planck Institute for Solid State Research is out today in the Journal of Vacuum Science and Technology A. In this work, Eren performed in situ experiments examining the surface reconstructions of Sr-doped La2CuO4 films grown by MBE. Using reflection high energy electron diffraction (RHEED), he tracked how the surface evolves during a shuttered growth routine in ozone and vacuum environments. Ph.D. student Patrick Gemperline applied the principle component analysis and K-means clustering codes developed in our lab by former postdoc Sydney Provence to track the evolution of these surface reconstructions and found that they match quite well to the shuttering times, supporting the conclusions from Eren’s experiments. Our contributions to the work were supported by our AFOSR Young Investigator grant.

LaFeO3 Thin Film OER Catalysis Study Published in Journal of Materials Chemistry A

Band alignment of LFO-n:STO interface vs. RHE

Our collaborative work with Prof. Byron Farnum’s group is out today in the Journal of Materials Chemistry A. This work was co-led by Andricus Burton in the Farnum group and Rajendra Paudel in FINO Lab and examines the role of film thickness on catalytic performance of LaFeO3 catalysts for the oxygen evolution reaction. It draws on Prof. Comes’ previous work on the band alignment of LaFeO3 with n-doped SrTiO3 to show how a combination of interfacial electronic reconstruction and the intrinsic high resistivity of LaFeO3 produce a sweet spot for catalysis at ~6 nm thickness. Electron microscopy work from Drs. Steven Spurgeon and Bethany Matthews as well as DFT modeling from Dr. Michel Sassi at Pacific Northwest National Laboratory helped to explain the complex physics and chemistry that occurs at the buried interface and film surface. The work is funded as part of the collaborative NSF grant between our two labs at Auburn.

Paper in Journal of Materials Research Chosen for Early Career Scholar Prize

Our group’s review article in the Journal of Materials Research has been chosen as the winner of the Early Career Scholar in Materials Science Prize by the journal editors with the Materials Research Society! This paper was the result of hard work by graduate students Suresh Thapa, Rajendra Paudel, Miles Blanchet, and Patrick Gemperline, who were co-first authors on it and wrote it during the height of the COVID pandemic in the spring and summer of 2020. Thanks to the many Zoom calls and revisions from everyone it is now a valuable resource for new researchers looking to integrate X-ray photoelectron spectroscopy into film growth! The video above is an interview with Dr. Comes and Prof. Gary Messing of Penn State University, who is the Editor-in-Chief of the journal. The press release from JMR is here.

Suresh Thapa Wins Alabama EPSCOR Graduate Research Fellowship

Suresh in the lab

Congrats to Suresh Thapa for winning the Alabama EPSCOR Graduate Research Scholars fellowship! Our lab is funded by an Air Force Office of Scientific Research (AFOSR) Young Investigator grant that was the first award made with support from the Defense EPSCOR program. Through that award, Suresh is now the first graduate student in Alabama history to receive the GRSP fellowship through Defense EPSCOR funding.

Paper on Pd3Bi2Se2 Epitaxial Films Published in APL Materials

Figure

Our collaborative paper with Oak Ridge National Lab has been published in APL Materials. This work focuses on the synthesis of topological parkerite films by MBE and is the first excursion of the FINO Lab into chalcogenide materials. Patrick Gemperline and Tami Isaacs-Smith performed Rutherford backscattering measurements on these samples to confirm film stoichiometry in the self-limited growth regime.

Paper on In Situ XPS of SrTiO3 Films Published in JVSTA

Suresh’s paper on in situ X-ray photoelectron spectroscopy studies of SrTiO3 films grown by hybrid MBE has been published in the Journal of Vacuum Science and Technology A as an Editor’s Pick! This is the first (but not last) paper to report in situ studies of films grown by the novel hybrid MBE method that has been developed for more than a decade. Our unique lab setup was designed specifically to perform this type of work. The article appears in the Special Collection honoring Dr. Comes’ post-doctoral advisor Scott Chambers, who is a leader in in situ XPS, making it particularly appropriate.

Our results show that Sr adatoms on the film surface catalyze the decomposition of the titanium tetraisopropoxide precursor that delivers the titanium cations. Films grown within the stoichiometric growth window have greater than expected concentrations of Sr on the surface, suggesting a partial or complete SrO termination. We collaborated with Prof. Wencan Jin and Dr. Jerzy Sadowski to perform low-energy electron microscopy (LEEM) measurements on films and with Prof. Petra Reinke and Devin Jessup of the University of Virginia to perform scanning tunneling microscopy (STM) on a sample.

These results are part of our ongoing effort to push hybrid MBE into a new regime that enables interfacial studies with different B site cations. Watch for more results over the next year!

Collaborative Paper on Fe2TiO4 Thin Films Published

Our collaborative paper led by Dr. Tiffany Kaspar of Pacific Northwest National Lab has been published in the Journal of Physics: Condensed Matter! Rajendra Paudel in our group and Tami Isaacs-Smith in the Auburn accelerator lab performed Rutherford back scattering analysis on the films to support the work. These interesting spinel oxides are good candidates for further studies as oxygen evolution and reduction catalysts, which is the focus of our ongoing NSF project in collaboration with Prof. Byron Farnum’s group.