Journal: Physical Review Materials

Abbreviation

Phys. Rev. Materials

Publisher

American Physical Society

Journal Volumes

ISSN

2475-9953

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2017 - 2019322020 - 202539
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Publications 1 - 10 of 71
  • Tailoring interfacial properties in CaVO3 thin films and heterostructures with SrTiO3 and LaAlO3: A DFT+DMFT study
    Item type: Journal Article
    Beck, Sophie; Ederer, Claude (2020)
    Physical Review Materials
    In this paper we use density functional theory combined with dynamical mean-field theory (DFT+DMFT) to study interface effects between the correlated metal CaVO3 and the two typical substrate materials SrTiO3 and LaAlO3. We find that the CaVO3/SrTiO3 interface has only a marginal influence on the CaVO3 thin film, with the dominant effect being the (bulklike) epitaxial strain imposed by the large lattice mismatch, rendering the CaVO3 film insulating due to the enhanced orbital polarization related to the strong level splitting between the t2g orbitals. In contrast, at the polar CaVO3/LaAlO3 interface, the presence of the interface can have a huge effect on the physical properties, depending both on the specific interface termination and on the specific boundary conditions imposed by the multilayer geometry. We compare three approaches to modeling the CaVO3/LaAlO3 interface, all of which impose a different set of (electrostatic) boundary conditions. Our results demonstrate that different substrates, interface terminations, and electrostatic boundary conditions can drastically affect the properties of thin-film heterostructures, indicating the potential tunability of the interfacial properties via multilayer engineering. (© 2020 American Physical Society.).
  • Untangling the structural, magnetic dipole, and charge multipolar orders in Ba2MgReO6
    Item type: Journal Article
    Mansouri Tehrani, Aria; Spaldin, Nicola (2021)
    Physical Review Materials
    We present a density functional theory study of the low-temperature structural, magnetic, and proposed chargequadrupolar ordering in the double perovskite, Ba2MgReO6. Ba2MgReO6 is a spin-orbit-driven Mott insulator with a symmetry lowering structural phase transition at 33 K and a canted antiferromagnetic ordering of 5d1 Re magnetic moments at 18 K. Our calculations confirm the existence of the proposed charge quadrupolar order and reveal an additional, previously hidden, ordered charge quadrupolar component. By separately isolating the structural distortions and the orientations of the magnetic dipoles, we determine the relationship between the charge quadrupolar, structural, and magnetic orders, finding that either a local structural distortion or a specific magnetic dipole orientation is required to lower the symmetry and enable the existence of charge quadrupoles. Our paper establishes the crystal structure–magnetic dipole–charge multipole relationship in Ba2MgReO6 and related 5d1 double perovskites, and illustrates a method for separating and analyzing the contributions and interactions of structural, magnetic, and charge orders beyond the usual dipole level.
  • Interstitial solute segregation at triple junctions: Implications for nanomaterials and a case study of hydrogen in palladium
    Item type: Journal Article
    Tuchinda, Nutth; Wagih, Malik; Schuh, Christopher A. (2025)
    Physical Review Materials
    At very fine grain sizes, grain boundary segregation can deviate from conventional behavior due to triple junction effects. While this issue has been addressed in prior work for substitutional alloys, here we develop a framework that accounts for interstitial sites in the grains, grain boundaries, and triple junctions of model Pd(H) polycrystals. This approach allows computation of interstitial segregation spectra separately at both defect types, which permits an understanding of segregation at all grain sizes via a size-scaling spectral isotherm. The size dependencies of dilute Pd(H) are found to be influenced not only by the triple junction content, but also by grain size–dependent lattice strains; the latter effect is evidenced by size dependencies of individual grain boundary and junction subspectra. The framework proposed here is applicable to interstitial alloys in general and may serve as a basis for interfacial engineering in interstitial nanocrystalline alloys. As an example, we show that using the dilute limit isotherm, hydrogen density can triple in nanocrystalline vis-à-vis microcrystalline Pd due to hydrogen adsorption at intergranular defect sites.
  • Single-dopant band bending fluctuations in MoSe2 measured with electrostatic force microscopy
    Item type: Journal Article
    Cowie, Megan; Plougmann, Rikke; Schumacher, Zeno; et al. (2022)
    Physical Review Materials
    In this paper, we experimentally demonstrate two-state fluctuations in a metal-insulator-semiconductor device formed out of a metallic atomic force microscopy tip, vacuum gap, and multilayer MoSe2 sample. We show that noise in this device is intrinsically bias dependent due to the bias-dependent surface potential and does not require that the frequency or magnitude of individual dopant fluctuations are themselves bias dependent. Finally, we measure spatial nonhomogeneities in band bending (charge reorganization) timescales.
  • Interplay between chemical order and magnetic properties in L1(0) FeNi (tetrataenite): A first-principles study
    Item type: Journal Article
    Izardar, Ankit; Ederer, Claude (2020)
    Physical Review Materials
  • Probing the small-scale plasticity and phase stability of an icosahedral quasicrystal i-Al-Pd-Mn at elevated temperatures
    Item type: Journal Article
    Cheng, Changjun; Xiao, Yuan; Haché, Michel J.R.; et al. (2021)
    Physical Review Materials
    Quasicrystalline materials possess a unique structure that is ordered yet not periodic. Despite their special configuration and many useful properties, they are typically very brittle at temperatures below ∼75% of their melting points, rendering them difficult to process and often unsuitable for practical implementations. Micro-compression offers an opportunity to unveil the fundamental mechanisms of quasicrystal plasticity. Here, we study the mechanical behavior of a typical icosahedral quasicrystal (i-Al-Pd-Mn) using microthermomechanical techniques over a temperature in the range 25–500 °C. We observe a few interesting phenomena, including micropillar shrinkage, phase transformations, grain refinement, and thermally induced transitions in deformation behavior (from brittle fracture at room temperature to serrated plastic flows and then to homogeneous flows at elevated temperatures). Furthermore, we discuss the multiple underlying mechanisms on the mechanical behavior of the quasicrystal in this temperature regime, exploring surface evaporation/diffusion, diffusion-enhanced plasticity, dislocation activities, and grain boundary rotation/sliding. Our study bridges the gap between room-temperature and high-temperature plasticity in quasicrystals, demonstrating an opportunity to study complex intermetallic phases in broad size and temperature regimes.
  • Zr-doped indium oxide electrodes: Annealing and thickness effects on microstructure and carrier transport
    Item type: Journal Article
    Rucavado, Esteban; Landucci, Federica; Döbeli, Max; et al. (2019)
    Physical Review Materials
  • Magnetophononics: Ultrafast spin control through the lattice
    Item type: Journal Article
    Fechner, Michael; Sukhov, Alexander; Chotorlishvili, Levan; et al. (2018)
    Physical Review Materials
  • Neutron scattering and muon-spin spectroscopy studies of the magnetic triangular-lattice compounds A₂La₂NiW₂ O₁₂ (A=Sr,Ba)
    Item type: Journal Article
    Yu, Bocheng C.; Yang, J.Y.; Gawryluk, Dariusz J.; et al. (2023)
    Physical Review Materials
    We report on the geometrically frustrated two-dimensional triangular-lattice magnets A₂La₂NiW₂ O₁₂ (A=Sr,Ba) studied mostly by means of neutron powder diffraction (NPD) and muon-spin rotation and relaxation (μSR) techniques. The chemical pressure induced by the Ba-for-Sr substitution suppresses the ferromagnetic (FM) transition from 6.3 K in the Ba compound to 4.8 K in the Sr compound. We find that the R3¯ space group reproduces the NPD patterns better than the previously reported R3¯m space group. Both compounds adopt the same magnetic structure with a propagation vector k=(0,0,0), in which the Ni2+ magnetic moments are aligned ferromagnetically along the c axis. The zero-field μSR results reveal two distinct internal fields (0.31 and 0.10 T), caused by the long-range FM order. The small transverse muon-spin relaxation rates reflect the homogeneous internal field distribution in the ordered phase and, thus, further support the simple FM arrangement of the Ni2+ moments. The small longitudinal muon-spin relaxation rates, in both the ferromagnetic and paramagnetic states of A₂La₂NiW₂ O₁₂ indicate that spin fluctuations are rather weak. Our results demonstrate that chemical pressure indeed changes the superexchange interactions in A₂La₂NiW₂ O₁₂ compounds, with the FM interactions being dominant.
  • Defect-induced magnetism and Yu-Shiba-Rusinov states in twisted bilayer graphene
    Item type: Journal Article
    Lopez-Bezanilla, Alejandro; Lado, José L. (2019)
    Physical Review Materials
Publications 1 - 10 of 71