Research Interests of Mike H. Whangbo
At Present my research efforts are focused on the following topics:
(1) Electronic Band Structures of Low-Dimensional Metallic Compounds
In understanding the transport and other physical properties of low-dimensional metallic compounds, it is essential to know how their electronic structures are related to their crystal structures. In this project we attempt to provide theoretical understanding for transport, optical and structural properties of various low-dimensional conducting materials, which include transition-metal compounds and organic conducting salts. To achieve this objective, we carry out electronic band structure, density of state and Fermi surface calculations. To probe the structure-property relationships governing these compounds, the calculated electronic structures of these compounds are analyzed from the viewpoint of chemical concepts such as orbital interaction, overlap and symmetry.
(2) Theoretical Study of Spin Exchange Interactions in Magnetic Solids
Physical properties of a magnetic solid are described by a spin-Hamiltonian, which is written in terms of pair-wise spin exchange interactions and the associated spin exchange parameters. When the magnetic susceptibility, neutron inelastic scattering or Raman scattering data of a magnetic solid are analyzed in terms of a spin-Hamiltonian, the spin exchange parameters are obtained as numerical fitting parameters needed to reproduce the experimental data. This project attempts to correlate such “experimental” parameters with the geometrical structure of a magnetic solid by performing electronic structure calculations for its spin dimers (i.e., the structural units containing two adjacent spin sites). In this project, the spin exchange parameters of a magnetic solid are determined using first principles electronic structure calculations. In addition, the trends in the spin exchange parameters of magnetic solids are explained on the basis of semi-empirical electronic structure calculations.