The study of structural, electronic and optical properties of double-walled carbon nanotube bundles under hydrostatic pressureX. Yang1 and G. Wu2
1 National Laboratory of Solid State, Microstructures and Department of Physics, Nanjing University Nanjing 210093, PRC
2 Department of Physics and Astronomy, California State University Northridge - Northridge, CA 91330, USA
received 9 August 2007; accepted in final form 14 December 2007; published February 2008
published online 23 January 2008
Combining a classical force field, a tight-binding model, and first-principle calculations, we have studied structural, electronic, and optical properties of double-walled carbon nanotube (DWNT) bundles under hydrostatic pressure. We find that the outer tube acts as a protection shield for the inner tube and the inner tube increases the structure stability and the ability to resist the pressure of the outer tube. Moreover, the collapsed structures of the double-walled carbon nanotube bundle called "parallel" and "in-between" are more stable than the one called "herringbone". The structural phase transition induces a pseudogap along the symmetry line . Furthermore, the optical properties change greatly after the collapse and a strong anisotropy appears in the collapsed structure. This provides an efficient experimental way to detect structural phase transitions in DWNT bundles.
73.22.-f - Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals.
78.67.-n - Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures.
61.46.-w - Nanoscale materials.
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