1992 Fiscal Year Final Research Report Summary
Design of phonon resonators based on semiconductor superlattices for the realization of phonon maser of THz-frequency range
| Project/Area Number |
03650001
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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 |
Applied materials
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| Research Institution | (Faculty of Engineering) Hokkaido University |
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Principal Investigator |
TAMURA Shin-ichiro Hokkaido University, Fac. of Engineering Associate Professor, 工学部, 助教授 (80109488)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Superlattices / Phonon / THz / Resonator / Resonance / Transmission / Nanometer / Double-barrieri |
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| Research Abstract |
In this project we first considered the ABA multi-suplerlattice structures consisting of two kinds of periodic superlattices A and B. Assuming GaAs and AlAs as the constituent layers of both A and B superlattices, we have shown by numerical calculations that the resonance transmission occurs in the THz-frequency range if the layer thicknesses are chosen in 10- to 100-A range. Specifically, we found that these resonance transmissions happen at frequencies within the frequency gaps of A superlattices, where the phonon transmission is prohibited in a pure A-superlattice system. In addition we studied the frequency dependence of the phonon transmission rate in these multi-superlattice systems.
Next, in order to analyze the physical reason for the resonance of phonons in the proposed systems, we developed the analytical calculation of transmission rate based on the transfer-matrix method. As a result we succeeded to derive a general formula for the resonance condition.
We also examined the transmission characteristics in a system where B superlattice is replaced with a bulk layer. The resonance condition in this system is derived as a function of various parameters of constituent materials. If A (superlattice) and B (single bulk layer) are stacked alternatively, a transmission peak splits into several isolated peaks. As the number of periods (consisting of A and B structures) is increased, those transmission peaks coalesce and make a broad transmission band. We could derive phonon dispersion relation for the latter case.
The phonon transmission characteristics in various multisuperlattice structures we found have opened up new possibilities for designing phonon-optics devices such as phonon filters, phonon mirrors and phonon resonators.
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