2007 Fiscal Year Final Research Report Summary
Systematic investigation of optical and electronic features of spin-charge-photon coupled systems
| Project/Area Number |
15104006
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Condensed matter physics II
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| Research Institution | The University of Tokyo |
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Principal Investigator |
GONOKAMI Makoto The University of Tokyo, Graduate School of Engineering, professor (70161809)
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| Co-Investigator(Kenkyū-buntansha) |
MIYANO Kenjiro Research Center for Advanced, Science and lhchnology, professor (90167677)
NAGAOSA Naoto The University of Tokyo, Graduate School of Engineerin, professor (60164406)
TOKURA Yoshinori The University of Tokyo, Graduate School of Engineerin, professor (30143382)
KANODA Kazushi The University of Tokyo, Graduate School of Engineerin, professor (20194946)
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| Project Period (FY) |
2003 – 2007
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| Keywords | spin-charge-photon coupled system / strongly correlated electron system / oxide electronics / photoinduced chase transition / nonlinear optical response / quantum phase / quantum spin Hall effect / time resolved magneto-optical soectroscopy |
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| Research Abstract |
By a combination of different expertises, we explored new electronic and optical functions arising from the strong coupling between the dielectric and magnetic responses of strongly correlated electron systems.
Miyano group : We developed thin-film fabrication technique that allows lattice deformations associated with the phase transition of strongly correlated systems. The films display persistent photo-induced insulator/metal transition, novel magnetoresistance, and stable two-phase coexistence. The full anisotropic properties are now accessible due to the mono-domain quality of the films.
Tokura group : We have explored unusual dielectric response caused by nontrivial spin textures. In a polar ferrimagnet, we have found the optical magnetoelectric effects such as nontrivial optical nonlinear Kerr rotation and directional dichroism as induced by the toroidal moments. Magnetically induced ferroelectrics is discovered, in cycloidal magnets in which the polarization can be largely modifie
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d by external magnetic field.
Kanoda group : We explored new quantum phases of molecular materials with spin-charge and charge-lattice coupling. We found an anomalous phase and superconductivity due to spin frustration and charge fluctuations in the vicinity of the Mott transition of spin liquid and observed the quantum critical fluctuations of lattice dimerization and charge transfer around the neutral-ionic transition.
Nagaosa group : We examined the novel quantum phenomena related to the Berry phase. Taking into account the disorder effect, we have constructed the unified and global theory of the anomalous and spin Hall effects and attained the good quantitative agreements with the experiments. We also developed the theory of spin Hall effect of light and excitons.
Gonokami group : We investigated new optical phenomena and functions in systems where electrons and holes are strongly correlated, including enhanced terahertz emission from Mn ion doped GaAs and strong mid- gap impurity-induced absorption associated with magnetic order. We also developed a highly sensitive polarimetry method that is applicable to non-contact Hall measurement. Less
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