| Project/Area Number |
06640427
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | OSAKA PREFECTURE UNIVERSITY (1995)
Tohoku University (1994) |
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Principal Investigator |
KAYANUMA Yosuke OSAKA PREFECTURE UNIVERSITY,COLLEGE OF ENGINEERING,PROFESSOR, 工学部, 教授 (80124569)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | level-crossing / nonadiabatic transition / Landau-Zener formula / quantum dissipation / phase relaxation / energy relaxation / decoherence / nonradiative process / Landau-Zener遷移 / 量子摩擦 / 非断熱トンネリング / 相互作用モード / 非断熱過程 / トンネル効果 |
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| Research Abstract |
We have investigated the effect of dissipation on the nonadiabatic processes at a level-crossing in condensed matter. By a model of extended Zener model where the interaction with a system of many-mode phonons are taken into account, we have studied the transition probability P at a level crossing by analytical consideration for the formal perturbation series with respect to the off-diagonal matrix element. Colsed expressions for P are obtained in various limiting situations of the physical parameters. Especially, a general formula describing the transition probability in the incoherent limit was obtained, which covers both the high temperature limit and the low temperature strong coupling lmit. Furthermore, numerical simulations of the transition dynamics were performed by introducing the damping hyper operator for the interaction mode of the phonon. The analytical results are well reproduced by the numerical calculation. In addition, the dynamics all over the parameter region was clarified by the numerical simulation.
The model was applied also to the problem of nonradiative transitions at localized centers in solids such as the DX centers in semiconductors. It is made clear that the system excited to the upper region of the adiabatic potential curves makes a hot transition to another state before it relaxs to the thermal equilibrium in the excited state, through the croosing region of the adiabatic potential curves.
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