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.

Dr. Comes Wins NSF CAREER Award

The lab got good news on a new research project, as Dr. Comes was awarded an NSF CAREER award from the Division of Materials Research. The 5 year grant provides $650k in research funding to pursue studies of oxide interfaces and superlattices in 4d and 5d systems grown by hybrid molecular beam epitaxy. You can read about the award here and see the NSF abstract here.

X-ray Diffraction System Installed

Our new Rigaku SmartLab XRD supported by an NSF Major Research Instrumentation grant was delivered in January and installed in the Chemistry building over the past two weeks. The FINO Lab and our collaborators in the Farnum group have each collected data on the system and now will be going through remote applications training on the system over the coming weeks. More good news for materials research infrastructure here at Auburn!

Paper on Co-Mn Spinel Films Published in Journal of Physics: Condensed Matter

Co (left) and Mn (right) K-edge X-ray absorption (top) and EXAFS (bottom) data

Miles’ paper on the electronic and structural properties of epitaxial Co1+xMn2-xO4 spinel thin films is now out in the Journal of Physics: Condensed Matter. In this paper we examine the role of the Jahn-Teller distortion in stabilizing the electronic structure of the material as well as Co and Mn ionic coordination and valence. We show the polarization-dependent X-ray absorption studies of these materials and observe a strong polarization dependence in the Mn K edge data due to the Jahn-Teller distortion that has not previously been observed in spinels. Through density functional theory modeling performed by Jonathan Heath and Prof. Marcelo Kuroda at Auburn, Rutherford back scattering performed by Tami Isaacs-Smith, X-ray absorption spectroscopy performed by Dr. Steve Heald at the Advanced Photon Source, along with spectroscopic ellipsometry performed by by Dr. Tiffany Kaspar, X-ray diffraction performed by Dr. Mark Bowden, and scanning transmission electron microscopy performed by Drs. Bethany Matthews and Steven Spurgeon (all at Pacific Northwest National Lab), this was truly a team effort! The paper will be appearing in the 2020 JPCM Emerging Leaders special issue.

Invited Review Article on In Situ XPS Published in Journal of Materials Research

MBE to XPS to MBE feedback loop

Our summer group writing project reviewing the integration of X-ray photoelectron spectroscopy (XPS) with oxide thin film synthesis is out in the Journal of Materials Research! This invited review for the Early Career Scholars issue focuses on ways to improve film growth using XPS, accurately interpret XPS data, and design experiments to probe charge transfer and band alignment at interfaces. We use this framework to review many of the current research areas focusing on interfaces in complex oxide heterostructures. One of the recurring themes is the importance of in situ studies to decouple the effects of interfacial phenomena from the effects of atmospheric exposure. We hope that an audience of film growers and spectroscopists will appreciate our perspective!

FINO Lab and Auburn Collaborators Win NSF MRI Grant for New X-ray Diffractometer

High-resolution XRD from SrTiO3-LaCrO3 superlattice [Comes et al. Adv. Mat. Interfaces, 2016]

Our group will soon have access to a state-of-the-art Rigaku SmartLab X-ray Diffractometer thanks to a new National Science Foundation grant through the Major Research Instrumentation program. Dr. Comes, Prof. Byron Farnum in Chemistry (a FINO Lab collaborator on our NSF project), and Profs. Majid Beidaghi, Peng Li, Tae-Sik Oh, and Masoud Mahjouri-Samani in the College of Engineering collaborated on the proposal. Each group will benefit from access to the system for X-ray reflectometry, reciprocal space maps, and high-resolution X-ray diffraction (XRD) of thin film materials. It will be the only high-resolution XRD in a university in the state of Alabama with an area detector for rapid data acquisition. The system will be installed during February and March and will be open to users from around the region as well as undergraduate students participating in the Auburn Collaborative Approaches Among Scientist and Engineers REU program. If outside users are interested in performing experiments, please contact Dr. Comes by email.