Showing papers by "Eugene J. Mele published in 2003"
TL;DR: A theory of the electron-hole interaction in the photoexcited states is developed, and the one-dimensional character and tubular structure introduces a novel relaxation pathway for carriers photo Excited above the fundamental band edge.
Abstract: The electronic band gaps measured in fluorescence spectroscopy on individual single wall carbon nanotubes isolated within micelles show significant deviations from the predictions of one electron band theory. We resolve this problem by developing a theory of the electron-hole interaction in the photoexcited states. The one-dimensional character and tubular structure introduce a novel relaxation pathway for carriers photoexcited above the fundamental band edge. Analytic expression for the energies and line shapes of higher subband excitons are derived, and a comparison with experiment is used to extract the value of the screened electron-hole interaction.
193 citations
TL;DR: In this paper, the authors combine ab initio, tight-binding methods and analytical theory to study the piezoelectric effect of boron nitride nanotubes.
Abstract: We combine ab initio, tight-binding methods and analytical theory to study piezoelectric effect of boron nitride nanotubes. We find that piezoelectricity of a heteropolar nanotube depends on its chirality and diameter andcan be understood starting from the piezoelectric response of an isolated planar sheet, along with a structure specific mapping from the sheet onto the tube surface. We demonstrate that a linear coupling between the uniaxial and shear deformation occurs for chiral nanotubes. Our study shows that piezoelectricity of nanotubes is fundamentally different from its counterpart in three-dimensional bulk materials.
132 citations
TL;DR: In this article, a theory for the mixing of the nanotubes' electronic states and C60s' orbitals was developed for examining isolated fullerene peapod structures.
Abstract: The scanning tunneling microscope (STM) is a powerful tool for examining the electronic structure of carbon nanostructures. We describe experiments in which the STM’s capabilities for atomic scale imaging, spectroscopy, and nanoscale manipulation have been used to examine isolated fullerene peapod structures. These measurements demonstrate that the array of encapsulated C60 molecules in a peapod induce periodic modifications in the nanotube’s local electronic structure. To understand these findings, we develop a theory for the mixing of the nanotubes’ electronic states and C60s’ orbitals. The theory provides a good description of the prominent features of the peapods’ local electronic structure as probed by STM spectroscopy.
2 citations