Development of first-principles condensed matter theory is the target of study. This is done by advancing computational methods and by performing large-scale simulations. The methodologies under development are (1) the many-body Greens’s function approach to the excited states of materials, via the solution of the Bethe-Salpeter equation within the GW approximation, (2) accurate wave function theory based on the antisymmetrized germinal power and the Pfaffian, in place of the conventional Slater determinant, and (3) density functional approach to the non-equilibrium and steady state of the electrochemical interface. Collaboration with experimental research groups is also an important theme. The theme includes (1) structural phase transition of a material under strong magnetic field, (2) thermodynamic stability of bioluminescent material, and (3) Dirac cone of novel thin films grown on surfaces, (4) design of electrocatalyst for the next-generation fuel cell.

Carbon nano-material and photo-absorption spectrum. Our calculation (GW + Bethe-Salpeter equation) improves over the conventional calculation (time-dependent DFT) and yields results comparable to experiment. It has become possible to reliably predict excited states of systems up to 200 atoms.

Electrochemical reaction and non-equilibrium steady state of the platinum-solution interface.

Research Subjects

First-principles calculation of excited states based on GW + Bethe-Salpeter equation

Accurate wave function theory based on antisymmetrized germinal power

First-principles calculation of electrochemical interface

^{†}Erratum: Improved modeling of electrified interfaces using the effective screening medium method [Phys. Rev. B 88 , 155427 (2013)]: I. Hamada, O. Sugino, N. Bonnet and M. Otani, Phys. Rev. B95 (2017) 119901.

First-principles description of van der Waals bonded spin-polarized systems using the vdW-DF+ <math> <mi>U</mi> </math> method: Application to solid oxygen at low pressure: S. Kasamatsu, T. Kato and O. Sugino, Phys. Rev. B95 (2017) 235120.

^{†*}Dirac Fermions in Borophene: B. Feng, O. Sugino, R.-Y. Liu, J. Zhang, R. Yukawa, M. Kawamura, T. Iimori, H. Kim, Y. Hasegawa, H. Li, L. Chen, K. Wu, H. Kumigashira, F. Komori, T.-C. Chiang, S. Meng and I. Matsuda, Phys. Rev. Lett.118 (2017) 096401 (1-6).