Publications

Showing 119 results for Author: Valentino R. Cooper

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  • Mar, 2026

    Journal

    Programmable Phase Selection between Altermagnetic and Noncentrosymmetric Polymorphs of MnTe on InP via Molecular Beam Epitaxy

    Phase selecting nearly degenerate crystalline polymorphs during epitaxial growth can be challenging yet critical to targeting physical properties for specific applications. Here, we establish how phase selectivity of altermagnetic and noncentrosymmetric polymorphs of MnTe can be programmed by subtle changes to the surface of lattice-matched InP substrates in molecular beam…

  • Feb, 2026

    Journal

    A Solid State Zwitterionic Plastic Crystal With High Static Dielectric Constant

    Solid materials with a high dielectric constant have a wide range of applications in the energy storage field. In this research, an imidazolium-based zwitterion is designed, synthesized, and confirmed to have a plastic crystal phase based on the following experimental and computational evidence: (i) the presence of long-range order with weak intermolecular forces and compe…

  • Dec, 2025

    Journal

    Real-Space Local Dynamics in 1,2,3-Triazole Using Inelastic Neutron Scattering

    Enhancing proton transport in polymer electrolytes is crucial for advancing next-generation solid-state batteries, yet our understanding of proton conductivity in nonaqueous environments remains limited due to a lack of atomic-scale insights. In this study, we investigated the atomic-scale dynamics of 1,2,3-triazole, a small molecule capable of dynamic hydrogen bonding, as…

  • Sep, 2025

    Journal

    Constraints on magnetism and correlations in RuO2 from lattice dynamics and Mössbauer spectroscopy

    We provide experimental evidence for the absence of a magnetic moment in bulk RuO2, a candidate altermagnetic material, by using a combination of Mössbauer spectroscopy, nuclear forward scattering, inelastic X-ray and neutron scattering, and density functional theory calculations. Using complementary Mössbauer and nuclear forward scattering, we determine the Ru magnetic hy…

  • Aug, 2025

    Journal

    Unraveling the pathway towards superionic transport in polymer electrolytes

    Ionic transport in polymers is critical for Li-ion batteries, fuel cells, flow batteries and many other energy storage and conversion technologies. A significant enhancement of ion conductivity in polymers may be achieved through an increase in the polarity of side chains and their self-organization into specific morphologies, which can potentially act as percolated ionic…

  • Aug, 2025

    Journal

    Selective reduction in epitaxial SrFe0.5Co0.5O2.5 and its reversibility

    Oxygen-vacancy engineering in transition metal oxides enables programmable functionalities by modulating the valence states and local coordination of constituents. Here, we report the selective reduction of cobalt ions in epitaxial SrFe0.5Co0.5O2.5 thin films under reducing gas environments, while iron ions remain unchanged. X-ray absorption spectroscopy reveals an absorpt…

  • May, 2025

    Journal

    Lattice Structure and Dynamics of Sparse Molecular Crystals: OsO4 and RuO4

    OsO4 and RuO4 are molecular oxides with unique tetrameric structures and rare +8 oxidation states. Accurately modeling their properties remains challenging for density functional theory (DFT) due to weak intertetramer interactions, which standard functionals fail to capture. Here, we show that the van der Waals (vdW)-corrected density functional (vdW-DF-optB86b) provides s…

  • Apr, 2025

    Journal

    Altermagnetic behavior in OsO2: Parallels with RuO2

    We investigate and compare the electronic structure of OsO2 with the extensively studied RuO2. Calculations show that OsO2 exhibits antiferromagnetism and spin splitting driven by crystal symmetry, a characteristic of altermagnetism and similar to RuO2. Examination of the Fermi surface, with and without spin-orbit coupling, reveals that OsO2 has lower Fermi group velocitie…

  • Mar, 2025

    Journal

    Database of Nonaqueous Proton-Conducting Materials

    This work presents the assembly of 48 papers, representing 74 different compounds and blends, into a machine-readable database of nonaqueous proton-conducting materials. SMILES was used to encode the chemical structures of the molecules, and we tabulated the reported proton conductivity, proton diffusion coefficient, and material composition for a total of 3152 data points…

  • Feb, 2025

    Journal

    MnRhBi3: A Cleavable Antiferromagnetic Metal

    Cleavable metallic antiferromagnets may be of use for low-dissipation spintronic devices; however, few are currently known. Here we present orthorhombic MnRhBi3 as one such compound and present a thorough study of its physical properties. Exfoliation is demonstrated experimentally, and the cleavage energy and electronic structure are examined by density functional theory c…

  • Dec, 2024

    Journal

    Using Data-Science Approaches to Unravel Insights for Enhanced Transport of Lithium Ions in Single-Ion Conducting Polymer Electrolytes

    Solid polymer electrolytes have yet to achieve the desired ionic conductivity (>1 mS/cm) near room temperature required for many applications. This target implies the need to reduce the effective energy barriers for ion transport in polymer electrolytes to around 20 kJ/mol. In this work, we combine information extracted from existing experimental results with theoretical c…

  • Dec, 2024

    Journal

    Enhanced anhydrous proton conductivity in azole phosphonic acid mixtures

    Azole molecules are investigated as potential candidates for proton conductors under anhydrous conditions. Since 1,2,3-triazole has the lowest melting point (Tm = 17 °C), it was blended with three phosphonic acid-containing molecules (small molecules with one and two phosphonic acids per molecule and a phosphonic acid polymer) to provide a source of excess protons to enhan…

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