ITR/AP, Simulations and Modelling of Carbon Nanotubes: A Study ofElectronic Correlations

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This award is made under the Information Technology Research initiative. Electronic devices are the underpinning of information technology. Present electronic devices are microscale in size. This limits the switching speed at which information can transfer. Nanoscale systems, including carbon nanotubes, have a great potential for a new generation of electronic devices with switching speeds a thousand times faster. However, as the size and dimensionality of electronic devices approach the nanoscale, the effect of correlations and disorder become crucial. Despite their importance, the effects of correlations and disorder remain a significant fundamental challenge to the physics community. A new computational approach will be developed to address this problem.The effects of disorder and correlations are now being studied experimentally in carbon nanotubes. These nanotubes form the smallest diameter quasi-one-dimensional conductors yet produced. The rich phenomena which arise from correlations in nanotubes include Luttinger liquid power law transport observed in single-wall nanotubes, and the recently observed superconductivity in ropes. The role of disorder is seen in the wide range of conductivities measured in metallic tubes.The dynamical cluster approximation (DCA) will be further developed to simulate models of carbon nanotubes. This new technique eliminates the finite-sized errors which can be especially large in one-dimensional systems; allows for the study of intertube coupling, as well as coupling to the tube environment; and, when combined with the Maximum Entropy Method, enables the study of the dynamical response of these systems.Key objectives of the project include the development of a computational tool set to study strongly correlated nanotubes and, as a consequence, develop an understanding of the temperture dependent properties in the two-chain model of a single-walled nanotube; the competition between disorder and correlations; the superconductivity in the two-chain modle and the role of intertube coupling; and the effect of long-range Coulomb forces.%%%This award is made under the Information Technology Research initiative. Electronic devices are the underpinning of information technology. Present electronic devices are microscale in size. This limits the switching speed at which information can transfer. Nanoscale systems, including carbon nanotubes, have a great potential for a new generation of electronic devices with switching speeds a thousand times faster. However, as the size and dimensionality of electronic devices approach the nanoscale, the effect of correlations and disorder become crucial. Despite their importance, the effects of correlations and disorder remain a significant fundamental challenge to the physics community. A new computational approach will be developed to address this problem.Key objectives of the project include the development of a computational tool set to study strongly correlated nanotubes and, as a consequence, develop an understanding of the temperture dependent properties in the two-chain model of a single-walled nanotube; the competition between disorder and correlations; the superconductivity in the two-chain modle and the role of intertube coupling; and the effect of long-range Coulomb forces.***