Atomistic treatment of nanotube-metal interfaces

As silicon-based devices progressively move down towards atomistic dimensions, there is a lot of interest in assessing post-CMOS devices of the quantum wire and quantum dot flavor. Understanding transport through nanotube-metal interfaces requires a combination of expertise belonging to different domains of research. One needs electronic structure calculations that do justice to the individual tube and metal bandstructures, surface physics calculations that describe the geometry and surface states of the relaxed metal-nanotube interfaces, quantum chemical codes that describe the bonding between the tube and metal atoms, electrostatic codes that describe charge and potential rearrangement driven by the workfunction difference between the tube and the metal, and quantum transport calculations that describe non-equilibrium transport through the interface under bias. In this article, we discuss how we can combine insights and techniques from these disparate disciplines into one unified formalism to generate an atomistic code for studying nanotube-metal interfaces. Such a natural partitioning is offered by the non-equilibrium Green´s function (NEGF) treatment of transport where we model the device bandstructure within a suitable Hamiltonian, the self-consistent electrostatic potential separately using Poisson´s equation, and the contact-induced shifting and broadening of the tube levels using self-energy matrices.