Abstract
Absorption line shapes associated with the stretch mode of bond-center hydrogen (HBC (+)) at 1794 cm-1 and the twofold degenerate mode of hydrogen near the tetrahedral site (H(-)) at 745 cm-1 in germanium are measured with infrared-absorption spectroscopy. The HBC (+) line shape measured at 10 K for the case of low hydrogen concentrations gives a lifetime between 15 and 23 ps. Similar in magnitude to the 7.8±0.2 ps observed for the same defect in silicon [M. Budde et al, Phys. Rev. Lett. 85, 1452 (2000)], this observation indicates that the lifetime of the bond-centered mode is largely insensitive to the phonon frequency distributions of the host material. Pure dephasing dynamics of hydrogen in germanium are studied by measuring the shape of the 1794- and 745-cm-1 lines as a function of temperature. These measurements are analyzed using a recently formulated exchange model for vibrational dephasing. The temperature dependence of the 1794-cm-1 line shape is attributed to thermal fluctuations in the occupation number of a pseudolocalized mode at 75±2 cm-1.
Original language | English |
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Article number | 035214 |
Pages (from-to) | 352141-352149 |
Number of pages | 9 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 65 |
Issue number | 3 |
Publication status | Published - Jan 15 2002 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics