Abstract: We present the quasiparticle band structure of ZnO in its zincblende (ZB) and rocksalt (RS) phases at the Γ point, calculated within the GW approximation. The effect of the pd hybridization on the quasiparticle corrections to the band gap is discussed. We compare three systems, ZB-ZnO which shows strong pd hybridization and has a direct band gap, RS-ZnO which is also hybridized but includes inversion symmetry and therefore has an indirect band gap, and ZB-ZnS which shows a weaker hybridization due to a change of the chemical species from oxygen to sulfur. The quasiparticle corrections are calculated with different numbers of valence electrons in the Zn pseudopotential. We find that the Zn20 + pseudopotential is essential for the adequate treatment of the exchange interaction in the self-energy. The calculated GW band gaps are 2.47 eV and 4.27 eV respectively, for the ZB and RS phases. The ZB-ZnO band gap is underestimated compared to the experimental value of 3.27 by ~ 0.8 eV. The RS-ZnO band gap compares well with the experimental value of 4.5 eV. The underestimation for ZB-ZnO is correlated with the strong pd hybridization. The GW band gap for ZnS is 3.57 eV, compared to the experimental value of 3.8 eV.

Abstract: Stable monolayer materials based on existing, well known and stable two-dimensional crystal fluorographene and molybdenum disulfide are predicted to exhibit a huge magnetocrystalline anisotropy when functionalized with adsorbed transition metal atoms at vacant sides. Ab initio calculations within the density-functional theory formalism were performed to investigate the adsorption of the transitional metals in a single S (or F) vacancy of monolayer molybdenum disulfide (or fluorographene). We found strong bonding of the transitional metal atoms to the vacant sites with binding energies ranging from 2.5 to 5.2 eV. Our calculations revealed that these systems with adsorbed metal atoms exhibit a magnetic anisotropy, specifically the structures including Os and Ir show a giant magnetocrystalline anisotropy energy of 31-101 meV. Our results demonstrate the possibility of obtaining stable monolayer materials with huge magnetocrystalline anisotropy based on preexisting, well known and stable two-dimensional crystals: fluorographene and molybdenum disulfide. We believe that the results obtained here are useful not only for deeper understanding of the origin of magnetocrystalline anisotropy but also for the design of monolayer optoelectronic devices with novel functionalities.

Abstract: The effect of B and P dopants on the band structure of Si nanowires is studied using electronic structure calculations based on density functional theory. At low concentrations a dispersionless band is formed, clearly distinguishable from the valence and conduction bands. Although this band is evidently induced by the dopant impurity, it turns out to have purely Si character. These results can be rigorously analyzed in the framework of effective mass theory. In the process we resolve some common misconceptions about the physics of hydrogenic shallow impurities, which can be more clearly elucidated in the case of nanowires than would be possible for bulk Si. We also show the importance of correctly describing the effect of dielectric confinement, which is not included in traditional electronic structure calculations, by comparing the obtained results with those of G(0)W(0) calculations.

Abstract: We expand on a recent study of a lattice model of interacting particles [Phys. Rev. Lett. 111, 110601 (2013)]. The adsorption isotherm and equilibrium fluctuations in particle number are discussed as a function of the interaction. Their behavior is similar to that of interacting particles in porous materials. Different expressions for the particle jump rates are derived from transition-state theory. Which expression should be used depends on the strength of the interparticle interactions. Analytical expressions for the self-and transport diffusion are derived when correlations, caused by memory effects in the environment, are neglected. The diffusive behavior is studied numerically with kinetic Monte Carlo (kMC) simulations, which reproduces the diffusion including correlations. The effect of correlations is studied by comparing the analytical expressions with the kMC simulations. It is found that the Maxwell-Stefan diffusion can exceed the self-diffusion. To our knowledge, this is the first time this is observed. The diffusive behavior in one-dimensional and higher-dimensional systems is qualitatively the same, with the effect of correlations decreasing for increasing dimension. The length dependence of both the self-and transport diffusion is studied for one-dimensional systems. For long lengths the self-diffusion shows a 1/L dependence. Finally, we discuss when agreement with experiments and simulations can be expected. The assumption that particles in different cavities do not interact is expected to hold quantitatively at low and medium particle concentrations if the particles are not strongly interacting.

Abstract: A classical two-dimensional (2D) model for an artificial atom is used to make a numerical exact study of elastic and nonelastic scattering. Interesting differences in the scattering angle distribution between this model and the well-known Rutherford scattering are found in the small energy and/or small impact parameter scattering regime. For scattering off a classical 2D hydrogen atom different phenomena such as ionization, exchange of particles, and inelastic scattering can occur. A scattering regime diagram is constructed as function of the impact parameter (b) and the initial velocity (v) of the incoming particle. In a small regime of the (b,v) space the system exhibits chaos, which is studied in more detail. Analytic expressions for the scattering angle are given in the high impact parameter asymptotic limit.

Abstract: We report on a molecular dynamics study of small classical two-dimensional clusters with ringlike configurations. We focus on the particles motion at low temperatures before the radial and angular melting sets in. It is shown that in magic number configurations a local radial melting of subshells occur, which is related to the intershell rotation.

Abstract: We studied the structural and spectral properties of a classical system consisting of a finite number of particles, moving in two dimensions, and interacting through a repulsive logarithmic potential and held together by an anisotropic harmonic potential. Increasing the anisotropy of the confinement potential can drive the system from a two-dimensional (2D) to a one-dimensional (1D) configuration. This change occurs through a sequence of structural transitions of first and second order which are reflected in the normal mode frequencies. Our results of the ground state configurations are compared with recent experiments and we obtained a satisfactory agreement. The transition from the 1D line structure to the 2D structure occurs through a zigzag transition which is of second order. We found analytical expressions for the eigenfrequencies before the zigzag transition, which allowed us to obtain an analytical expression for the anisotropy parameter at which the zigzag transition occurs as a function of the number of particles in the system.

Abstract: In a recent paper, Arita et al. [Phys. Rev. E 90, 052108 (2014)] consider the transport properties of a class of generalized exclusion processes. Analytical expressions for the transport-diffusion coefficient are derived by ignoring correlations. It is claimed that these expressions become exact in the hydrodynamic limit. In this Comment,we point out that (i) the influence of correlations upon the diffusion does not vanish in the hydrodynamic limit, and (ii) the expressions for the self- and transport diffusion derived by Arita et al. are special cases of results derived in Becker et al. [Phys. Rev. Lett. 111, 110601 (2013)].