In this chapter the electrodynamics of the conduction electrons of carbon nanotube (CNT) are described, and models are derived to study the propagation of signals along CNT interconnects. The conduction electrons are seen as a fluid moving under the influence of the collective field and of the interaction with the fixed ion lattice. The transport equation is derived in the quasi-classical limit, allowing the formulation of a frequency domain constitutive equation for the CNTs, in terms of a nonlocal Ohm’s law. The CNT conductivity is strongly influenced by two parameters, which account for the electron inertia and for the quantum pressure. The conductivity may be expressed in terms of the effective number of conducting channels, a parameter that counts the number of subbands significantly involved in the conduction. The model is then extended to the case of interacting CNT shells, where the tunneling effect is considered. Self and mutual conductivities are then defined to account for this phenomenon. By coupling the above CNT constitutive equations to Maxwell equations, a transmission line model is derived, able to describe the propagation of signals along CNT bundles, in terms of simple RLC distributed lines. The intershell tunneling occurring at terahertz is then accounted for, with a suitable recasting of the transmission line equations, which now include spatial dispersion terms.
Carbon Nanotubes: from Electrodynamics to Signal Propagation Models
MAFFUCCI, Antonio;
2013-01-01
Abstract
In this chapter the electrodynamics of the conduction electrons of carbon nanotube (CNT) are described, and models are derived to study the propagation of signals along CNT interconnects. The conduction electrons are seen as a fluid moving under the influence of the collective field and of the interaction with the fixed ion lattice. The transport equation is derived in the quasi-classical limit, allowing the formulation of a frequency domain constitutive equation for the CNTs, in terms of a nonlocal Ohm’s law. The CNT conductivity is strongly influenced by two parameters, which account for the electron inertia and for the quantum pressure. The conductivity may be expressed in terms of the effective number of conducting channels, a parameter that counts the number of subbands significantly involved in the conduction. The model is then extended to the case of interacting CNT shells, where the tunneling effect is considered. Self and mutual conductivities are then defined to account for this phenomenon. By coupling the above CNT constitutive equations to Maxwell equations, a transmission line model is derived, able to describe the propagation of signals along CNT bundles, in terms of simple RLC distributed lines. The intershell tunneling occurring at terahertz is then accounted for, with a suitable recasting of the transmission line equations, which now include spatial dispersion terms.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.