MSE Colloquium: Michael Susner, Functional van der Waals Materials: A New Avenue for Next-Generation Electronics
All dates for this event occur in the past.
2040 Fontana Labs
140 W. 19th Ave.
Columbus, OH 43210
United States
Dr. Michael Susner
Research Materials Engineer (DR-02), Materials and Manufacturing Directorate, Air Force Research Laboratory
Abstract
Correlated two-dimensional (2D) materials offer a new avenue for the development of next-generation electronic devices. Since the discovery of Dirac physics in graphene, research in 2D materials has grown exponentially with two main aims:
- the discovery of new 2D materials
- developing new and innovative techniques to harness and tune their optical, magnetic, and electronic properties.
Though most research on 2D materials has focused on graphene, boron nitride, and transition metal chalcogenides (TMCs), new 2D materials classes are coming into the forefront, including metal thiophosphates (1) which, in many ways, are the 2D equivalent of complex oxides as changes in composition, stacking, or pressure in turn lead to large changes in bandgap (2), magnetic ordering temperature and type (1), ferroelectric ordering temperature (1,3), possible Kitaev physics (4) (i.e. quantum spin liquids) and even the appearance of superconductivity (5).
I shall present the materials characterization of CuInP2S6 and related self-assembled CuInP2S6/In4/3P2S6 heterostructures as a case study for this materials class in particular and 2D materials in general to show how the underlying physics is affected by chemical and structural modifications.
When alloyed with excess In, the compound spontaneously forms self-assembled heterostructures as the material is cooled from a cation liquid state where mobile Cu and In cations exist within a rigid [P2S6]4- framework. Upon freezing, the disordered cation sublattice separates into two distinct phases, one of which is ferroelectric (CuInP2S6). The presence of these self-assembled heterostructures imparts strain to the ferroelectric phase and increases its TC (3). The functionality of the CuInP2S6 phase is determined by the details of the phase separation (i.e. nanoconfinement of the CuInP2S6 domains suppresses ferroic ordering)(6, 7) which in turn is affected by temperature and pressure. I will also discuss recent efforts in materials characterization where our team determined that the heterostructured phase evinces a tunable quadruple potential well for the ferroelectric phase (8).
Finally, I will discuss recent experimental efforts on the 2D multiferroic CuCrP2S6 compound (9).
Bio
Michael A. Susner earned his B.S. in Chemistry (2005) from Michigan State University and his M.S. (2009) and PhD. (2012) in Materials Science and Engineering from The Ohio State University. From 2014-2016 he was a Postdoctoral Research Fellow in the Correlated Electron Materials Research Group at Oak Ridge National Laboratory. He joined the Air Force Research Laboratory in 2017 as a NRC Fellow and worked in the Soft Matter Materials Branch in the Materials and Manufacturing Directorate as a UES Research Scientist from 2019 to 2020. He became a staff scientist for AFRL in the Photonic Materials Branch in 2020 in order to establish a crystal growth center at AFRL. He is interested in establishing structure-property correlations in functional materials, i.e. those evincing magnetic, ferroelectric, and superconducting behaviors. His current research focuses on the development of materials for second harmonic generation for laser conversion and for quantum information materials.
9. Susner, M. A., Rao, R., Pelton, A. T., McLeod, M. V. & Maruyama, B. Temperature-dependent Raman scattering and x-ray diffraction study of phase transitions in layered multiferroic CuCrP2S6. Phys. Rev. Mater. 4, (2020).