E. N. Bogachek

Properties of Metallic Nanowires: From Conductance Quantization to Localization

Material structures of reduced dimensions exhibit electrical and mechanical properties different from those in the bulk. Measurements of room-temperature electronic transport in pulled metallic nanowires are presented, demonstrating that the conductance characteristics depend on the length, lateral dimensions, state and degree of disorder, and elongation mechanism of the wire. Conductance during the elongation of short wires (length l ∼ 50 angstroms) exhibits periodic quantization steps with characteristic dips, correlating with the order-disorder states of layers of atoms in the wire predicted by molecular dynamics simulations. The resistance R of wires as long as l ∼ 400 angstroms exhibits localization characteristics with In R(l) ∼ l2.

Energetics, forces, and quantized conductance in jellium-modeled metallic nanowires

Energetics and quantized conductance in jellium-modeled nanowires are investigated using the localdensity-functional-based shell correction method, extending our previous study of uniform-in-shape wires @C. Yannouleas and U. Landman, J. Phys. Chem. B 101, 5780 ~1997!# to wires containing a variable-shaped constricted region. The energetics of the wire ~sodium! as a function of the length of the volume-conserving, adiabatically shaped constriction, or equivalently its minimum width, leads to the formation of self-selecting magic wire configurations, i.e., a discrete configurational sequence of enhanced stability, originating from quantization of the electronic spectrum, namely, formation of transverse subbands due to the reduced lateral dimensions of the wire. These subbands are the analogs of shells in finite-size, zero-dimensional fermionic systems, such as metal clusters, atomic nuclei, and 3 He clusters, where magic numbers are known to occur. These variations in the energy result in oscillations in the force required to elongate the wire and are directly correlated with the stepwise variations of the conductance of the nanowire in units of 2 e 2 /h. The oscillatory patterns in the energetics and forces, and the correlated stepwise variation in the conductance, are shown, numerically and through a semiclassical analysis, to be dominated by the quantized spectrum of the transverse states at the most narrow part of the constriction in the wire. @S0163-1829~98!01908-0#

Electrical and mechanical properties of metallic nanowires: Conductance quantization and localization

Measurements of room‐temperature electronic transport in pulled metallic nanowires are presented, demonstrating that the conductance characteristics depend on the length, lateral dimensions, state and degree of disorder, and elongation mechanism of the wire. Conductance during elongation of short wires, l∼50 A, exhibits periodic quantization steps with characteristic dips, correlating with the order‐disorder states of layers of atoms in the wire, predicted via molecular dynamics simulations. The resistance of longer wires, l≳100 A, exhibits localization characteristics with ln R(l)∼l2. Effects of disorder and variations in wire geometry, exhibited via their influence on the transmittivity of the conductance channels and/or the quantization conditions, are demonstrated.

Thermoelectric effects in a Luttinger liquid

Thermoelectric effects in a Luttinger liquid (LL) wire adiabatically connected to the leads of noninteracting electrons are considered. For a multichannel LL a staircase-like behavior of the thermal conductance as a function of chemical potential is found. The thermopower for a LL wire with an impurity is evaluated for two cases: (i) LL constriction, and (ii) infinite LL wire. We show that the thermopower is described a Mott-like formula renormalized by an interaction-dependent factor. For an infinite LL the renormalization factor decreases with increase of the interaction. However, for a realistic situation, when a LL wire is connected to the leads of noninteracting electrons (LL constriction), the repulsive electron-electron interaction enhances the thermopower. A nonlinear Peltier effect in a LL is briefly discussed.

A magnetic-field-effect transistor and spin transport

A magnetic-field-effect transistor is proposed that generates a spin-polarized current and exhibits a giant negative magnetoresistance. The device consists of a nonmagnetic conducting channel (wire or strip) wrapped, or sandwiched, by a grounded magnetic shell. The process underlying the operation of the device is the withdrawal of one of the spin components from the channel, and its dissipation through the grounded boundaries of the magnetic shell, resulting in a spin-polarized current in the nonmagnetic channel. The device may generate an almost fully spin-polarized current, and a giant negative magnetoresistance effect is predicted.

Aharonov-Bohm effect and plasma oscillations in superconducting tubes and rings

Low frequency plasma oscillations in superconducting tubes are considered. The emergence of two different dimensionality regimes of plasma oscillations in tubes, exhibiting a crossover from one-dimensional to two-dimensional behavior, depending on whether

Phase-controlled force and magnetization oscillations in superconducting ballistic nanowires.

k R\ll 1

Chiral effects in normal and superconducting carbon nanotube-based nanostructures

or

Nonlinear Peltier effect in quantum point contacts

k R\gg 1

Spin-Polarized Current in a Nonmagnetic Conductor and the Role of Electron–Electron Scattering

, where