PHY 913 (Sect. 301):
Foundations of Nanoscale Science and Technology
David Tomanek
Fall 2011
Topic 2: Nanotubes
- Formation and Decay of Nanotubes
- Introduction
- Nanotubes: From an overlooked by-product
of fullerenes to a super-star
- Tubular carbon allotropes: single-wall nanotubes,
multi-wall nanotubes, ropes=bundled nanotubes
- Challenging problems:
- Isomer selectivity during synthesis
- Equilibrium structures
- Stability of nanotubes under extreme conditions:
- Morphology of Nanotubes
- From a graphene sheet to a nanotube
- Achiral and chiral nanotubes; single-wall, multi-wall,
and bundled nanotubes; zigzag and armchair nanotubes
- Euler's Theorem in cylindrical and defective nanotubes
- Production Techniques of Nanotubes
- Carbon arc bulk synthesis in presence and absence of
catalysts
- High-purity material (bucky paper) production using
Pulsed Laser Vaporization (PLV) of pure and doped graphite
- High-pressure CO conversion (HIPCO) nanotube synthesis
based on Boudoir reaction
- Chemical Vapor Deposition (CVD) synthesisof aligned
nanotube films
- Growth of Single-Wall Nanotubes
- Experimental puzzles: high yield,
universality of diameter, role of metal catalyst
- Key question: shape of baby-tube?
- Application of continuum elasticity theory to nanotubes
- Tube diameter optimization in a finite system
- Continuous growth by addition of carbon an the open edge
- Role of metal catalyst: scooter or policeman?
- Termination of growth
- Growth of Multi-Wall Nanotubes
- Experimental puzzles: aspect ratio, perfection,
chemical inertness
- Key question: independent or concerted growth?
- Consequences of the lip-lip interaction
- Equilibrium structure of double-wall nanotubes
- Structure stability at the growing edge
- Termination by a multi-walled dome
- Genealogy of Fullerenes and Nanotubes Revisited
- Nanotube stability and decay at high temperatures
- Thermal stability/melting point similar to
fullerenes and graphite
- Decay at high temperatures: Transition to 1D structures
at the edge (
movie).
- Nanotube stability and decay under high mechanical stress
- Unusually high Young's modulus
- Simulated cutting of a nanotube (movie).
- Nanotube stability and decay in strong electric fields
- Experimental puzzles: high stability,
large emission current,
discrete fluctuations in the emission current
- Key question: Microscopic structure at the tip?
- Decay by unraveling atomic wires
- Structural and Electronic Properties of Nanotubes
- Introduction
- Structural changes in free-standing and interacting
nanotubes: Librations, rotations, twistons
- Effect of inter-tube interactions on
the electronic structure
- Electronic structure of graphite as building block
of nanotubes
- Structure and dynamics of interacting tubes
- Equilibrium structure of nanotube ropes
- Inter-tube interactions and orientational ordering
- Orientational dislocations in frustrated
twisted, interacting tubes
- Mapping on a lattice gas of twistons
- Orientational melting of tubes
- Electronic structure of nanotubes
- Ignoring atomic positions: The layered jellium model
- Effect of chirality and discrete atoms:
Conducting versus insulating nanotubes
- Band structure of metallic carbon nanotubes:
dominant contribution of two pp-pi bands at EF
- Band structure of interacting metallic nanotubes:
The fatal touch that opens a gap
- Density of states of isolated and interacting
metallic nanotubes: Van Hove singularities and pseudogaps
- Effect of doping on conductivity
- Dipole response of nanotubes:
no surprises since fullerenes and graphite
- Application of Carbon Nanotubes
- Harnessing field enhancement: Flat-panel displays
- Harnessing tensile strength: Nano-velcro
- Controversy about Hydrogen Storage
- Summary and Conclusions
- Nanotubes as a unique self-assembling system
- Unusual properties: stability, thermal,
electric conductance
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