Resonant interaction between localized and extended vibrational modes in Si: 18O under pressure

Area of Science:

• Solid-state physics
• Vibrational spectroscopy
• Materials science

Background:

• Understanding vibrational mode interactions is crucial for solid-state physics.
• Interstitial oxygen (O(i)) in silicon serves as a model system for studying local vibrational modes.
• Phonon interactions govern energy transfer and relaxation processes in solids.

Purpose of the Study:

• To investigate the interaction between localized and extended vibrational modes in silicon.
• To study the decay of local vibrational modes into phonons.
• To explore the effect of hydrostatic pressure on vibrational mode interactions.

Main Methods:

• Utilized infrared spectroscopy to observe vibrational modes.
• Applied hydrostatic pressure up to 4 GPa to induce resonance.
• Studied the antisymmetric stretch mode of (18)O(i) and its resonant mode.

Main Results:

• Observed an anticrossing phenomenon between the antisymmetric stretch mode and the second harmonic of the resonant mode of (18)O(i) near 4 GPa.
• Demonstrated resonance between localized and extended vibrational modes under hydrostatic pressure.
• Achieved excellent agreement between experimental data and theoretical modeling.

Conclusions:

• Hydrostatic pressure can be used to tune vibrational mode interactions in solids.
• The observed anticrossing provides direct evidence of the coupling between local and extended vibrational modes.
• The study offers insights into phonon-limited linewidths and vibrational energy relaxation mechanisms in semiconductors.