Molybdenum selenide molecular wires as one-dimensional conductors

Scanning tunneling microscopy (STM) has been used to characterize the struc ture and electronic properties of molybdenum selenide (Mo6Se6) molecular wi res. STM images resolved the 0.45 nm unit cell repeat in isolated molecular wires and bundles of wires, Tunneling spectroscopy measurements exhibit sh arp peaks in the local density of states that are consistent with the Van H ove singularities expected for a one-dimensional (1D) system. These data ha ve been compared with previous band structure calculations. Preliminary mea surements at 5 K show no evidence of a gap opening at low temperatures. The implications of these results to metal-insulator transitions in 1D systems are discussed.