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Optical properties and surface termination of pristine and intercalated GeI<sub>2</sub>

ORAL

Abstract

GeI2 is an understudied layered material that can be exfoliated easily down to a monolayer, owing to its low cleavage energy of 0.16 J/m2 [1], which is smaller than that of graphite. Large single crystals of GeI2 (space group 164, P-3m1) have now been grown, including crystals intercalated with pyridine, aniline and triethylamine. GeI2 has a thermal stability even at 600 K and the band gap is tunable through intercalation, which makes GeI2 an interesting optoelectronic material. We have confirmed that GeI2 multilayer has an intrinsic band gap of 2.59 ± 0.01 eV, which is consistent with theoretical expectations [1]. Ergo, electronics based on GeI2 may find applications in high temperature devices. Furthermore, angle resolved x-ray photoemission spectroscopy (ARXPS) measurements demonstrate that GeI2 terminates in iodine, and multilayer GeI2 has a significant surface to bulk core level shift. While we have not yet confirmed ferromagnetism in GeI2 single crystals, it does have a temperature dependent moment, and the impact of phonons is being explored.

[1] C. S. Liu, X. Le Yang, J. Liu, et al., J. Phys. Chem. C 122, 22137 (2018). DOI: 10.1021/acs.jpcc.8b05529

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Presenters

  • Archit Dhingra

    Physics and Astronomy, University of Nebraska - Lincoln

Authors

  • Archit Dhingra

    Physics and Astronomy, University of Nebraska - Lincoln

  • Katerina Chagoya

    Mechanical and Aerospace Engineering, University of Central Florida

  • Joseph Dalton

    Florida Space Institute, University of Central Florida

  • Richard Blair

    Physics, University of Central Florida, Florida Space Institute, University of Central Florida

  • Peter A Dowben

    Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska - Lincoln, Department of Physics and Astronomy, University of Nebraska-Lincoln, University of Nebraska - Lincoln