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We report the discovery of superconductivity and detailed normal-state physical properties of RbV3Sb5 single crystals with V kagome lattice. RbV3Sb5 single crystals show a superconducting transition at Tc ~ 0.92 K. Meanwhile, resistivity, magnetization and heat capacity measurements indicate that it exhibits anomalies of properties at T* ~ 102 - 103 K, possibly related to the formation of charge ordering state. When T is lower than T*, the Hall coefficient RH undergoes a drastic change and sign reversal from negative to positive, which can be partially explained by the enhanced mobility of hole-type carriers. In addition, the results of quantum oscillations show that there are some very small Fermi surfaces with low effective mass, consistent with the existence of multiple highly dispersive Dirac band near the Fermi energy level., 6 pages, 4 figures

We theoretically study the spin-polarized transport phenomena of the parallel double quantum dots coupled to two ferromagnetic leads by the Anderson Hamiltonian. The Hamiltonian is solved by means of the equation-of-motion approach. We analyse the transmission probability of this system in both the equilibrium and nonequilibrium cases, and our results reveal that the transport properties show some noticeable characteristics depending upon both the spin-polarized strength p and the value of the magnetic flux . Moreover, in the parallel configuration, the position of the Kondo peak shifts while it remains unchanged for the antiparallel configuration. These effects might have some potential applications in spintronics.

We theoretically investigate the spin-polarized transport properties of the T-shaped double quantum dots coupled to two ferromagnetic leads by the Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We calculate the density of states and the liner conductance in this system with both parallel and antiparallel lead-polarization alignments, and our results show that the transport properties of this system depend on both the tunnelling strength between the two dots and the spin-polarized strength p. This system is a possible candidate for spin valve transistors in the spintronics.

Nanocomposite FePt–C thin films were prepared by a pulsed filtered vacuum arc deposition technique. The films were characterized by non-Rutherford backscattering spectrometry, x-ray diffraction, and magnetic force microscopy. The dependence of magnetic properties against annealing temperature was studied by using a vibrating sample magnetometer. Both x-ray diffraction and magnetic force microscopy analyses confirmed the formation of nano-crystallites of face-centred-tetragonal phase of FePt in the carbon matrix after annealing at a sufficiently high temperature. For the film with a composition of (Fe0.55Pt0.45)0.78C0.22, the coercivity and the grain size were observed to increase with increasing annealing temperature, up to a value of 3.5 kOe at an annealing temperature of 650 degrees C, and with a grain size about 10.5 nm.

The one-dimensional super-symmetric ferromagnetic t-J model is studied via the thermal Bethe ansatz. Analytic expressions of the free energy for T→0 are obtained. A new critical behaviour beyond the universal class of Luttinger liquids is found in this system.

Magnetic and structural properties of YCo12-xTix compounds have been investigated by x-ray diffraction and magnetic measurements. X-ray diffraction patterns of aligned powder samples indicate that the easy magnetization direction at room temperature is along the c-axis for all the compounds. The lattice parameters increase monotonously while Curie temperature TC decreases with increasing Ti content. It was found that all the compounds investigated are strong ferromagnets by analysis of magnetic moments using a magnetic valence model. The values of anisotropy fields Ba at room temperature and 1.5 K decrease with increasing x. The easy-axis anisotropy of the YCo12-xTix compounds is mainly contributed by the Co atoms at 8i sites according to the individual-site-anisotropy model.

Contact geometry and electronic transport properties of a silicon atom sandwiched between Au electrodes in three different anchoring configurations are investigated by using the density functional theory combined with the non-equilibrium Green function method. We simulate the nanoscale junction breaking process and calculate the corresponding cohesion energy, obtain the equilibrium conductance and the projected density of states of junctions in an optimal postion. We also calculate the conductance and the current of junctions at the equilibrium position under small bias voltage. It is found that all junctions have large conductance and show a linear I—V relationship, but the current and conductance of a hollow-hollow configuration is always the biggest under the voltage range of −1.2 V~1.2V. The calculated results proved that the coupling morphology of a silicon atom connected with electrodes has an important effect on the electronic transport properties of the nanoscale junction.

The 2D magnetophonon oscillatory in GaAs-AlxGa1-xAs hetero-structure interface, grown by MBE, has been investigated by means of the second derivative of the magnetoresistance under high pulsed magnetic fields up to 40T. The fundamental magnetic field has been measured as 23.7T and the damping facter γ, 2D electron effective mass m* for our sample are 1.58 and 0.0747me, respectively.

Using a high pulsed magnetic field system up to 200kOe, we have investigated the magnetic properties of (Nd1-xTbx)16.7Fe75.5B7.8 (x=0, 0.05, 0.1, 0.2, 0.4) at a temperature range 77-450K. The results show that the spin reorientation temperature Ts decreases with the increase of x.