Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5404215 | Journal of Luminescence | 2006 | 5 Pages |
Abstract
We investigate the high-pressure phase of Bi under hydrostatic pressure using pump-probe spectroscopy at pressures up to 3.0Â GPa, and we observe coherent phonons signal and relaxation signal of photo-excited carriers at Bi(II) and Bi(III) phases. The pressure dependence of the coherent phonons shows that the amplitude of coherent phonons is extremely small and the frequency of coherent phonons changes at high-pressure phases. As results from our experiment, we obtain its frequencies are 2.5 and 2.2Â THz at Bi(II) and Bi(III), respectively. Furthermore, photo-excited carrier relaxation indicates drastic changes near 2.5Â GPa. Bismuth transforms from semimetal to semiconductor near 2.5Â GPa, and band-overlapping between at L-point and at T-point disappears. We consider that the drastic changes of the photo-excited carrier relaxation are strongly correlated with the band-overlapping disappearing.
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
M. Kasami, T. Ogino, T. Mishina, S. Yamamoto, J. Nakahara,