Using an empirical many‐body potential and a genetic algorithm, the geometries of small V3 to V19 clusters have been optimized. We find that the clusters do not mimic the bulk structure and undergo significant geometrical changes with size. Based on the optimization geometries, the d electronic structure and magnetic properties of V clusters are studied, by using a Hubbard tight‐binding model Hamiltonian in the unrestricted Hartree‐Fock approximation. The calculated average magnetic moments for these clusters are consistent with the upper limits obtained from experiments. The total density of states (TDOS) and the local density of states (LDOS) of d electrons shed light on the evolution of the electronic properties.

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Subject classification: 61.46.þw; 73.22.Àf; 75.50.Tt; S1.2Using an empirical many-body potential, we performed Genetic Algorithm (GA) to determine the ground-state atomic configurations of V 13Àx Rh x (x ¼ 0 to 13) clusters. The lowest-energy structures of both bimetallic and pure ðx ¼ 0 and 13Þ clusters are deformed icosahedra. In general, there is a tendency for Rh atoms to be segregated at the surfaces of the bimetallic clusters, although this effect can coexist with ordering. Based upon the optimized geometries, the ground state electronic and magnetic properties of these clusters are calculated by using an spd-band model Hamiltonian in the unrestricted Hartree-Fock approximation. Due to the strong coupling of the electronic states of Rh and V atoms, the electronic structure and the magnetism of these clusters vary completely with the change in the ratio of the two classes of atoms. The average magnetic moments per atom for Rh and V atoms m Rh , m nV , as well as the average magnetic moment m m for these clusters oscillate as functions of the numbers x of Rh atoms.

By using a decomposition elimination method for Green's function, the transport properties of Graphenenanoribbon-based quantum dot (QD) and/or QD superlattice are studied. It is shown that relatively small changes of both QD size and magnetic field intensity can induce strong variations in the electron transmission across the structure. For a QD device, electrons can be either totally reflected or totally transmitted through the QD region at some energies, and the quasibound peaks have been observed to have a small shift due to quasibound state energy varying. In the case of QD superlattice, the electrons within the miniband energy region can transmit through a device, similar to a QD device. Therefore, the transmission spectrum can be tailored to match with requirement by modulating the size of quantum dot and the number 𝑝 of superlattce.