RESEARCH INTERESTS

• First-principles study of electronic transport in nanostructures such as carbon nanotubes and molecular electronic devices.

• Theoretical investigation of superconducting properties of novel superconductors on the basis of first-principles calculation.

• Ab-initio calculation of physical properties of solids and molecules including crystal structures, electronic structures, and vibrational spectra.

RESEARCH ACCOMPLISHMENTS

• Superconducting mechanism of MgB₂: First-principles investigation of MgB₂ including the electronic structure, phonon spectra, electron-phonon interactions, superconducting transition temperature, isotope effects, structure of the superconducting energy gap on the Fermi surface, quasi-particle excitation spectra, and specific heat using the anisotropic Eliashberg formalism.

• Structure and Electronic Structure of C₆₀ Monolayers: First-principles study of the atomic geometries and electronic structures of C₆₀ monolayers on metal surfaces for the comparison with the experimental results of high-resolution angle-resolved photoemission spectroscopy.

• Electronic Structure of Carbon Nanotube Junctions: Calculation of the local density of states in carbon nanotube intramolecular junctions for the analysis of scanning tunneling spectroscopic data.

• First-principles Method for the Calculation of Conductance in Quantum Wires: Development of computational formalism for the conductance of atomic wires based on the ab initio nonlocal pseudopotential method.

• Electronic Transport in Carbon Nanotubes with Defects: First-principles calculation of the conductance of carbon nanotubes with substitutional boron and nitrogen impurities; pentagon-heptagon-pair defects; and carbon vacancies. Analytic calculation of conductance of armchair carbon nanotubes with defects within a simple tight-binding model.

• Crossed Carbon Nanotube Junctions: First-principles calculation of conductance of crossed metallic carbon nanotube junctions as a function of applied forces.

• Electronic Structure of Carbon Nanotube Ropes: Prediction of pseudogap opening by broken symmetry in the electronic structure of bundles of armchair metallic carbon nanotubes.

• Excitonic Tunneling Rate in Al_xGa_1-xAs/GaAs Double Quantum Wells: Numerical calculation of tunneling probability through a three-dimensional percolative barrier as a model for excitonic tunneling through an Al_xGa_1-xAs barrier in Al_xGa_1-xAs/GaAs double quantum wells.