@article{oai:niigata-u.repo.nii.ac.jp:00002127,
 author = {Yamakawa, Youichi and Mitsumoto, K. and Ono, Yoshiaki},
 issue = {Supplement A},
 journal = {Journal of the Physical Society of Japan, Journal of the Physical Society of Japan},
 month = {Apr},
 note = {Recently, Goto et al. have discovered the anomalous elastic softening due to vacancy in crystalline silicon in the low-temperature ultrasonic measurements. To investigate the quantum state of the silicon vacancy, we introduce a cluster model which includes both the Coulomb interaction between electrons in the dangling bond and the coupling between the electrons and Jahn-Teller phonons. We solve the model by using the numerical diagonalization method and find that the V + state which has spin S = 1/2 is stable with the trigonal mode phonon while unstable with the tetragonal mode phonon. The obtained result is consistent with the newly observed experiment., Proceedings of International Conference on New Quantum Phenomena in Skutterudite and Related Systems (Skutterudite2007)},
 pages = {266--268},
 title = {Effects of Electron Correlation and Electron-phonon Coupling on the quantum state of a Silicon Vacancy},
 volume = {77},
 year = {2008}
}