2001 Fiscal Year Final Research Report Summary
Many-Body Effect and Cooperative Phenomena in High-Density Exciton Systems Driven by Light
| Project/Area Number |
11215206
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (B)
|
| Allocation Type | Single-year Grants |
|---|
| Review Section |
Science and Engineering
|
|---|
| Research Institution | NARA INSTITUTE OF SCIENCE AND TECHNOLOGY |
|---|
Principal Investigator |
AIHARA Masaki Nara Institute of Science and Technology Graduate School of Materials Science, Professor, 物質創成科学研究科, 教授 (70091163)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
INAGAKI Takeshi Nara Institute of Science and Technology Graduate School of Materials Science, Research Associate, 物質創成科学研究科, 助手 (10253139)
TAKAHASHI Akira Nara Institute of Science and Technology Graduate School of Materials Science, Associate Professor, 物質創成科学研究科, 助教授 (80212009)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Keywords | Exciton / Bose-Einstein condensation / Macroscopic quantum state / Electron correlation / Superconductivity / BCS state |
|---|
| Research Abstract |
We have presented for the first time the unified theory of luminescence spectra for highly excited electron-hole systems which is applicable both to the electron-hole BCS state and to the exciton BEC state. The multiple Coulomb interaction between electron-hole pairs is taken into account by numerically solving the Bethe-Salpeter equation for electron-hole pair correlation function. The effect of the collective quantum fluctuation associtated with the center-of-mass motion of electron-hole pairs is incorporated by the generalized random-phase approximation. The crossover from the exciton BEC to the electron-hole BCS state clearly manifests itself in the calculated luminescence spectra.
We have also investigated photo-generated states in strongly correlated electron systems. We have derived the effective Hamiltonian of the Hubbard model for the multi-photon excited states assuming sufficiently large on-site repulsive Coulomb interaction. We have calculated two-photon excited states for a system with 20 sites in the half-filled case with exactly diagonalizing the effective Hamiltonian. We have found that the correlation function for the d-wave superconductivity has finite values even for large distance. This strongly suggests that the photo-induced superconductivity arises in strongly correlated electron systems.
|
