title: Limits to metallic conduction in atomic-scale quasi-one-dimensional silicon wires.
abstract: The recent observation of ultralow resistivity in highly doped, atomic-scale silicon wires has sparked interest in what limits conduction in these quasi-1D systems. Here we present electron transport measurements of gated Si:P wires of widths 4.6 and 1.5 nm. At 4.6 nm we find an electron mobility, μ(el)≃60  cm²/V s, in excellent agreement with that of macroscopic Hall bars. Metallic conduction persists to millikelvin temperatures where we observe Gaussian conductance fluctuations of order δG∼e²/h. In thinner wires (1.5 nm), metallic conduction breaks down at G≲e²/h, where localization of carriers leads to Coulomb blockade. Metallic behavior is explained by the large carrier densities in Si:P δ-doped systems, allowing the occupation of all six valleys of the silicon conduction band, enhancing the number of 1D channels and hence the localization length.
authors.affiliation: Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: Bent
authors.initials: B
authors.lastname: Weber
authors.affiliation: National Institute of Supercomputing and Networking, KISTI, Daejeon 305-806, South Korea.
authors.forename: Hoon
authors.initials: H
authors.lastname: Ryu
authors.affiliation: Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Y-H Matthias
authors.initials: YH
authors.lastname: Tan
authors.affiliation: Network for Computational Nanotechnology, Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Klimeck
authors.affiliation: Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: Michelle Y
authors.initials: MY
authors.lastname: Simmons