The structure, stability, and electronic properties of PdnAu (n = 3~20) clusters are studied by density functional theory. The results show that the clusters studied here prefer three-dimensional structures even with very small atom number. It is found that the binding energies of PdnAu clusters are higher than the corresponding pure Pdn clusters with the same atom number. Most PdnAu clusters studied here are magnetic with magnetic moments ranging from 1.0 to 7.0 μB. The dissociation energies of Pd atoms are lower than the doped gold atom, that is the doped Au atom will increase the mother clusters stability and activity.

•The electronic structure of CdSe nanosheet under different strain is studied.•CdSe nanosheet transforms from semiconductor to metal under symmetrical strain.•The band structure of CdSe nanosheets can be manipulated under various strains.We report a first principles study on the electronic structure of CdSe nanosheet under strain. Our results suggest that the band structure of CdSe nanosheet experiences a transition from being semiconducting to metallic with increased symmetrical strain. Such transition is not found under asymmetrical (along zigzag or armchair direction) strain. Moreover, the band gap of CdSe nanosheet responds differently among symmetrical, zigzag and armchair strain. A detailed discussion on the strain dependence effect is also presented via the electron localization function, the charge transfer between Cd and Se atoms, and the evolution of energy states at Γ and K point.Band gap of CdSe nanosheet under symmetrical and asymmetrical strain. A semiconductor-to-metal (S–M) transition is found when symmetrical strain strength reaches 0.1.

We have studied the pressure-induced structural transition of ZnO nanocrystals using constant pressure molecular dynamics simulations for finite system. We have observed the transition from the fourfold coordination wurtzite to the sixfold coordination rocksalt structure, and the process of transition is strongly dependent on the morphology of the nanocrystals. It is found that the perfect faceted ZnO nanocrystals undergo wurtzite to rocksalt transition with a perfect fivefold h-MgO structure as the intermediate status. But for the faceted ones without perfect surface structure, as the number of the atoms removed from the (0 0 1) and (001¯) surface edge increases, the local morphology will become more similar to spherical. The nanocrystal will receive equal stress from every direction and it will be more difficult to compress the structure along only c axis as the perfect faceted ZnO nanocrystal. In this situation, only partial structure experiences intermediate fivefold coordination structure or even no intermediate fivefold coordination structure exists dependent on the surface disorder level.Highlights► The structural transition of ZnO nanocrystals is investigated by MD simulation. ► The volume and relative coordination are used to analyze the structural transition. ► Effects of the surface disorder level and shape are discussed.

•The torsional properties of Cu NWs supported by CNTs were investigated by MD simulation.•The size and temperature effects on the torsional properties of Cu NWs were studied.•Cu NWs can bear larger torsional angle at low torsional rates and high temperatures due to CNTs.The torsional mechanical properties of hollow Cu nanowires supported by carbon nanotubes (CNTs) are studied by all atoms molecular dynamic simulation. It is found that the critical angles of Cu nanowires almost do not decrease when the temperature increases to a limit value, and this invariant feature also has been found as the torsional loading rate is lower than 4.5×1012°s−1. Due to the support of CNTs, Cu nanowires can bear larger torsional angle at low torsional rates and high temperatures compared with those without CNTs, which means the CNTs will increase the torsion-tolerance of Cu nanowires.