To develop self-consistent first-principles calculation methods for real materials and to understand the physical properties of transition metal oxides and related systems (so-called strongly correlated materials) by applying various theoretical methods.


Research Interest:

Materials with strong electron correlations have been one of the most intriguing subjects in condensed matter physics. Advances in synthesis and characterization of novel metal-oxide compounds with exotic properties such as high Tc superconductivity, colossal magneto-resistance, and multi-ferroic orderings have led to possible applications of strongly correlated materials with artificially combined nanoscale structures of metal oxides. Understanding the physical properties of 'real' materials with strong electron correlations still requires a detailed knowledge on the electronic, magnetic, and structural configurations due to strong Coulomb interactions. As a step toward the investigation of metal oxide nanostructures, we developed a first-principles LDA+U (local density approximation + on-site Coulomb interaction U) method by extending the state-of-the-art O(N) DFT (density functional theory) method. The capability of carrying out large-scale electronic structure calculations with both LDA+U and O(N) methods is a key to the theoretical investigation of the large scale systems with strongly electron correlation effects ranging from nanoscale structures of metal oxides to the biological molecules. One of the topics under current investigations is defects and defect complex in transition-metal oxides and their role in the determination of transport characteristics of doped oxides and other related systems, which is a long standing issue to be resolved for the applications of correlated materials. When our approach becomes successful, we hope to contribute to the understanding of the physics of various materials with strong electron correlations by providing a clear picture for the correlated phenomena at nanoscale metal oxides and in biological molecules.

Other Links: