Physical Review B

Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review

I. Introduction (Preface, Nanostructures in Si Inversion Layers, Nanostructures in GaAs-AlGaAs Heterostructures, Basic Properties). 
II. Diffusive and Quasi-Ballistic Transport (Classical Size Effects, Weak Localization, Conductance Fluctuations, Aharonov-Bohm Effect, Electron-Electron Interactions, Quantum Size Effects, Periodic Potential). 
III. Ballistic Transport (Conduction as a Transmission Problem, Quantum Point Contacts, Coherent Electron Focusing, Collimation, Junction Scattering, Tunneling). 
IV. Adiabatic Transport (Edge Channels and the Quantum Hall Effect, Selective Population and Detection of Edge Channels, Fractional Quantum Hall Effect, Aharonov-Bohm Effect in Strong Magnetic Fields, Magnetically Induced Band Structure).

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Quantum Transport in Semiconductor Nanostructures

Publisher Summary Quantum transport is conveniently studied in a two-dimensional electron gas (2DEG) because of the combination of a large Fermi wavelength and large mean free path. Semiconductor nanostructures are unique in offering the possibility of studying quantum transport in an artificial potential landscape. This is the regime of ballistic transport in which scattering with impurities are neglected. The chapter presents a self-contained account of these three novel transport regimes in semiconductor nanostructures. The study of quantum transport in semiconductor nanostructures is motivated by more than scientific interest. The fabrication of nanostructures relies on sophisticated crystal growth and lithographic techniques that exist because of the industrial effort toward the miniaturization of transistors. Conventional transistors operate in the regime of classical diffusive transport, which breaks down on short length scales. The discovery of novel transport regimes in semiconductor nanostructures provides options for the development of innovative future devices.

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Quantum coherent effects, phase transitions, and the dissipative dynamics of ultra small tunnel junctions

Time of Zener tunneling.

A computational model was developed to study the thermal conductivity of single-walled carbon nanotube (SWNT)-polymer composites. A random walk simulation was used to model the effect of interfacial resistance on the heat flow in different orientations of SWNTs dispersed in the polymers. The simulation is a modification of a previous model taking into account the numerically determined thermal equilibrium factor between the SWNTs and the composite matrix material. The simulation results agreed well with reported experimental data for epoxy and polymethyl methacrylate (PMMA) composites. The effects of the SWNT orientation, weight fraction and thermal boundary resistance on the effective conductivity of composites were quantified. The present model is a useful tool for the prediction of the thermal conductivity within a wide range of volume fractions of the SWNTs, so long as the SWNTs are not in contact with each other. The developed model can be applied to other polymers and solid materials, possibly even metals.

https://iopscience.iop.org/article/10.1088/0957-4484/19/6/065702/pdf

Computational modeling of the thermal conductivity of single-walled carbon nanotube-polymer composites.

We present a theoretical study of the current‐voltage characteristic of a new transistor based upon the ‘‘Coulomb blockade.’’ In mesoscopic (submicron) tunnel junctions the flow of current can be blocked by the electrostatic charging energy of a single electron. The charge‐effect transistor is composed of two mesoscopic tunnel junctions connected in series with a gate terminal capacitively coupled to the interjunction region. Such a device has been shown to lead to a Coulomb staircase in the current‐voltage characteristic when the gate voltage is zero. Here we study the effect of the gate voltage on the current through the device for various ranges of junction parameters. We study junctions made from both normal metal and superconductors. We examine the current noise at different operating points and find it comparable to, but lower than, that in ordinary shot‐noise devices.

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The charge‐effect transistor

Using molecular dynamics (MD) simulations, we study thermal transport in graphene nanoribbons (GNR) subjected to uniform uniaxial and nonuniform strain fields. We predict significant thermal rectification (over $70%$) in a rectangular armchair GNR by applying a transverse force asymmetrically. The heat flux is larger from the less stressed region to the more stressed region. Furthermore, we develop a theoretical framework based on the nonequilibrium thermodynamics to discuss when thermal rectification under a stress gradient can occur. We conclude with a discussion of details relevant to experiment.

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Tunable thermal transport and thermal rectification in strained graphene nanoribbons

We present experimental and theoretical results on bound states in quantum wires (narrow, two-dimensional quantum channels). We study rectangular systems of constant width, varying the bend angle. This system is realized by propagation of TE-mode microwaves in flat rectangular waveguides; resonant frequencies for absorption of power are measured for various bend angles, and compared with theoretical results for bound-state (resonant) eigenvalues

Kieran Mullen

Papers

Time of Zener tunneling.

Computational modeling of the thermal conductivity of single-walled carbon nanotube-polymer composites.

The charge‐effect transistor

Tunable thermal transport and thermal rectification in strained graphene nanoribbons

Bound states and resonances in waveguides and quantum wires.