Abstract:
Defect-related photoconductivity of single ZnO nanowires is investigated. The photoconductivity shows power-law dependence with incident green laser intensity due to the defect mechanisms including both recombination centres and traps. The device based on single ZnO nanowire shows a sensitive photoresponse to green light with significant on/off ratios. In addition, the photocurrent is highly sensitive to the polarization of the incident illumination. Therefore, the nanowire may act as apolarized photodetector.

Abstract:
Spin-dependent transport through a quantum-dot (QD) ring coupled to ferromagnetic leads with noncollinear magnetizations is studied theoretically. Tunneling current, current spin polarization and tunnel magnetoresistance (TMR) as functions of the bias voltage and the direct coupling strength between the two leads are analyzed by the nonequilibrium Green's function technique. It is shown that the magnitudes of these quantities are sensitive to the relative angle between the leads' magnetic moments and the quantum interference effect originated from the inter-lead coupling. We pay particular attention on the Coulomb blockade regime and find the relative current magnitudes of different magnetization angles can be reversed by tuning the inter-lead coupling strength, resulting in sign change of the TMR. For large enough inter-lead coupling strength, the current spin polarizations for parallel and antiparallel magnetic configurations will approach to unit and zero, respectively. PACS numbers:

Abstract:
The thermal entanglement in the triangular molecular spin ring with Dzyaloshinskii--Moriya interaction is studied. The concurrences of arbitrary two spins of the triangular molecular spin ring for various cases are evaluated. The tendency of the concurrence with Dzyaloshinskii--Moriya interaction and temperature is analysed and discussed. We note that the concurrence arrives at its maximum in the regime with the large Dzyaloshinskii--Moriya interaction and low temperature, and gradually decreases to zero with the increase of temperature. The concurrence has different features for the ferromagnetic and antiferromagnetic cases. For completeness, we also numerically calculate the concurrence of spin rings with N>3 spins and analyse their behaviours.

Abstract:
In the title compound, C12H12O3, the methoxy and prop-2-ynyloxy groups are nearly coplanar with the attached benzene ring [C—O—C—C torsion angles = 1.2 (3) and 2.2 (3)°, respectively]. In the crystal, inversion dimers linked by pairs of C—H...O interactions occur.

Abstract:
The title molecule, C17H19NO5, was prepared by a Hantzsch dihydropyridine synthesis from 4-hydroxybenzaldehyde, methyl acetoacetate and NH4HCO3. In the molecular structure of the title compound, the dihydropyridine ring adopts a flattened boat conformation and the plane of the base of the boat forms a dihedral angle of 80.8 (2)° with the aromatic six-membered ring. The packing is stabilized by strong intermolecular N—H...Ocarbonyl, Ohydroxy—H...Ocarbonyl and weak intramolecular C—H...O hydrogen bonds.

Abstract:
The $XYZ$ antiferromagnetic model in linear spin-wave frame is shown explicitly to have an $su(1,2)$ algebraic structure: the Hamiltonian can be written as a linear function of the $su(1,2)$ algebra generators. Based on it, the energy eigenvalues are obtained by making use of the similar transformations, and the algebraic diagonalization method is investigated. Some numerical solutions are given, and the results indicate that only one group solution could be accepted in physics.

Abstract:
We investigate a tight-binding model of the octahedron-decorated cubic lattice with spin-orbit coupling. We calculate the band structure of the lattice and evaluate the Z_2 topological indices. According to the Z_2 topological indices and the band structure, we present the phase diagrams of the lattice with different filling fractions. We find that the $(1;111)$ and $(1;000)$ strong topological insulators occur in some range of parameters at 1/6, 1/2 and 2/3 filling fractions. Additionally, the $(0;111)$ weak topological insulator is found at 1/6 and 2/3 filing fractions. We analyze and discuss the characteristics of these topological insulators and their surfaces states.

Abstract:
In the title compound, C21H25NO4, the dihydropyridine ring adopts a flattened boat conformation. The N atom and the sp3 C atom deviate in the same direction from the mean plane of the other four C atoms, by 0.269 (6) and 0.111 (6) , respectively. This mean plane is inclined to the 4-methoxyphenyl ring by 87.3 (5)°. The cyclohexenone ring has a sofa conformation with the C atom bearing the methyl groups deviating from the mean plane through the other five C atoms by 0.628 (6) . There is a short C—H...O hydrogen bond in the molecule. In the crystal, molecules are linked by an N—H...O hydrogen bond to form chains propagating along the c-axis direction.

Abstract:
We investigate the spectrum and eigenstates of ultracold fermionic atoms in the bilayer honeycomb optical lattice. In the low energy approximation, the dispersion relation has parabolic form and the quasiparticles are chiral. In the presence of the effective magnetic field, which is created for the system with optical means, the energy spectrum shows an unconventional Landau level structure. Furthermore, the experimental detection of the spectrum is proposed with the Bragg scattering techniques.

Abstract:
We study quantum phases of ultracold bosonic atoms in a two-dimensional optical superlattice. The extended Bose-Hubbard model derived from the system of ultracold bosonic atoms in an optical superlattice is solved numerically with Gutzwiller approach. We find that the modulated superfluid(MS), Mott-insulator (MI) and density-wave(DW) phases appear in some regimes of parameters. The experimental detection of the first order correlations and the second order correlations of different quantum phases with time-of-flight and noise-correlation techniques is proposed.