We perform first-principles calculation of the transport properties of alumium-phosphorus dopped Si atomic nanowire coupled to two Al(100) nanoscale electrodes using the non-equilibrium Green formalism combined with the density-functional theory. In particular, the alumium-phosphorus dopped silicon wire with seven atoms sandwiched between the Al(100) electrodes is considered. It is found that the transport properties are sensitive to the dopping position of the alumium and the phosphorus on the silicon wire. The equilibrium conductance of the pure silicon wire is rather big, close to 3 G0, Three eigenchannels which contribute to the equilibrium conductance are fully open. All cases of the alumium-phosphorus dopping reduce the conductivity of the pure silicon wire. In particular, the conductance of the wire decreases to 0.7 G0 when a phosphorus substitutes the third silicon atom and a alumium substitutes the sixed silicon atom. The current-voltage(I-V) curves of these cases vary dramatically. The current across the wire with a phosphorus substitutes the third silicon atom and a alumium substitutes the sixed silicon atom is rather smaller than the that across the pure silicon. A detailed analysis of the transmission coefficient of the eigenchannels, the projected density of states are made to reveal the mechanism of the differences.

A molecular dynamics simulation study has been performed for a system consisting of 15,000 atoms to investigate the formation and magic number characteristics of various clusters formed during the rapid solidification. Results indicate that the icosahedral cluster (12 0 12 0) plays key role in the glass transition. The size distribution of clusters in the system showing magic number characteristics, and the magic number sequence in the Mg2Ca system is 13, 19, 25, 36, 37, ....This magic number sequence is quite similar with that of the system of metal Al.

The molecular dynamics simulation studies on the microstructure evolution properties of amorphous Ca7Mg3 alloy during the isothermal annealing have been performed. The simulated structure factor S(q) of Ca7Mg3 is well agreed with the experimental data. Results indicate that the metallic glass of Ca7Mg3 alloy is relaxed into amorphous structure of greater stability in which much more icosahedron structures is formed; interestingly, it is also found that the short short-range order has no change, while the short-range order of the system increases during the isothermal annealing process.

The transport properties of transition metal atoms interfered alpha-graphyne nanoribbon systems are investigated by first-principles calculations combined with the Keldysh nonequilibrium Green’s method. In all, five types of configurations are considered. We find that intervention of three Cr atom in alpha-graphyne nanoribbon systems decreases the conductivity of the system. Further study show that the magnetic direction of the electrode infulence the spin filtering effect greatly, while the ralative magnetic direction of the three transition Cr atoms have little effect on the transport properties. At finite bias window, negative differential resistance happens. Proper analysis are given to explain the spin filtering phenonmenon and the different transport properties via transmission coefficient and projected density of states.

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