| Popis: |
In this Letter, a phonon spectrum of YBCO is obtained from its experimental specific heat data by an exact inversion formula with eliminating divergence parameter [Dai Xianxi, Xu Xinwen and Dai Jiqiong, Proceedings of Beijing International Conference on High T c Superconductivity, Sept. 4–8 Beijing, China, (1989) 521], [Dai Xianxi, Xu Xinwen and Dai Jiqiong, Phys. Lett. A 147 (1990) 445]. The results are comparable to that from neutron inelastic scattering. Some key points of specific heat-phonon spectrum inversion (SPI) theory as well as a method of asymptotic behavior control are discussed. An improved unique existence theorem is presented. A universal function set for the numerical calculation in SPI is obtained, which will make the inversion method applicable and convenient in practice. This is the first time to realize the specific heat-phonon spectrum inversion in a concrete system. |
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