Materials Literature
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Stoichiometric Mn 0.2 Zn 0.8 Fe 2 O 4 monodisperse nanoparticles were prepared by the so-called polyol method. The variation of magnetization as a function of magnetic field H (up to ±50 kOe) and temperature (5−320 K) were investigated, for zero-field-cooled (ZFC) and field-cooled (FC) conditions on freshly produced p…
We review our research towards single-crystal growth of epitaxial few-layer graphene (FLG) on SiC substrates. We have established a method for evaluating the number of graphene layers microscopically using low-energy electron microscopy. Scanning probe microscopy in air is also useful for estimating the number-of-laye…
The aim of the present work was to investigate the influence of Cu substitution on the physicochemical properties of LaCo 1− x Cu x O 3 ( x = 0, 0.1, and 0.2) prepared by the sol−gel method, to clarify the relation between perovskite properties and their catalytic behaviors in the catalytic wet aerobic oxidation (CWAO…
By forming an ultrathin (∼100 nm) SiC film on Si substrates and by annealing it at ∼1500 K in vacuo, few-layer graphene is formed on Si substrates. Graphene grows on three major low-index surfaces: (1 1 1), (1 0 0) and (1 1 0), allowing us to tune its electronic properties by controlling the crystallographic orientati…
We report a first-principles investigation aiming at controlling the stabilization and catalytic activity of metal nanoclusters supported on graphene via tuning the mechanical strain in graphene. We show that a relatively modest tensile strain (10%) applied in graphene greatly increases the adsorption energies of vari…
We demonstrate that graphene nanoribbons (GNRs), produced by the chemical unzipping of carbon nanotubes, can be conveniently used from solution to hand-paint unidirectional arrays of GNRs atop silicon oxide. Through this simple alignment technique, numerous GNR-based devices, including field effect transistors, sensor…
Since its inception in 2001, the science and technology of epitaxial graphene on hexagonal silicon carbide has matured into a major international effort and is poised to become the first carbon electronics platform. A historical perspective is presented and the unique electronic properties of single and multilayered e…
Oligo(thienylenevinylene) (OTV) based gelators with high conductivity are reported. When compared to OTV1, OTV2 having an increased conjugation length forms relatively strong gels with a metallic conductivity of 4.8 S/cm upon doping which is the highest value reported for an organogelator. This new class of conducting…
An effective Hamiltonian scheme is developed to investigate structural and magnetic properties of ${\text{BiFeO}}_{3}$ nanodots under short-circuit-like electrical boundary conditions. Various striking effects are discovered. Examples include (a) scaling laws involving the inverse of the dots' size for the magnetic an…
A parallelized hybrid Monte Carlo (HMC) methodology is devised to quantify the microstructural evolution of polycrystalline material under elastic loading. The approach combines a time explicit material point method (MPM) for the mechanical stresses with a calibrated Monte Carlo (cMC) model for grain boundary kinetics…
An extended one-dimensional defect that has the potential to act as a conducting wire has been embedded in another perfect graphene sheet.
Sliding parts in nanosystems such as Nano ElectroMechanical Systems (NEMS) and nanomotors, increasingly involve large speeds, and rotations as well as translations of the moving surfaces; yet, the physics of high speed nanoscale friction is so far unexplored. Here, by simulating the motion of drifting and of kicked Au…
Calculations within density functional theory on the basis of the local density approximation are carried out to study the properties of intrinsic point defects in aluminum antimonide. Special care is taken to address finite-size effects, band gap error, and symmetry reduction in the defect structures. The correction…
Based on numerically accurate density functional theory (DFT) calculations, we systematically investigate the ground-state structure and the spin and orbital magnetism including the magnetic anisotropy energy (MAE) of 3d- and 4d-transition-metal dimer benzene complexes (TM2Bz, TM = Fe, Co, Ni, Ru, Rh, Pd; Bz = C6H6).…
The thermodynamic stabilities of various phases of the nitrides of the platinum metal elements are systematically studied using density functional theory. It is shown that for the nitrides of Rh, Pd, Ir and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower format…
Short-range order (SRO) in Fe-rich Fe-Cr alloys is investigated by means of atomistic off-lattice Monte Carlo simulations in the semi-grand canonical ensemble using classical interatomic potentials. The SRO parameter defined by Cowley [Phys. Rev. B 77, 669 (1950)] is used to quantify the degree of ordering. In agreeme…
We perform first-principles density-functional calculations to explore the role of substrate proximity effects on the octahedral rotation patterns in perovskite oxide superlattices. With cubic perovskite ${\text{SrFeO}}_{3}$ as our model film and tetragonal ${\text{SrTiO}}_{3}$ as the substrate, we show that in most c…
Generally there are two strategies in fitting the measured structural relaxation time of glass-forming liquids: the single-formula approach e.g. the Vogel-Tammann-Fulcher equation,and the multi-branch approach. In this note, a two-branch method was presented. By analyzing existing single- and multi-branch approaches,…
Diamond has received increasing attention for its promising biomedical applications. The material is highly biocompatible and can be easily conjugated with bioactive molecules. Recently, nanoscale diamond has been applied as light scattering labels and luminescent optical markers. The luminescence, arising from photoe…
The varying metallic antiferromagnetic correlations observed in iron-based superconductors are unified in a model consisting of both itinerant electrons and localized spins. The decisive factor is found to be the sensitive competition between the superexchange antiferromagnetism and the orbital-degenerate double-excha…