Acoustic vibration coupling of gold nanoplates at low temperatures

The study investigates the acoustic vibration coupling in a Gold-PVP-Gold nanostructure at low temperature (78K) using a femtosecond pump-probe spectroscopy. The experimental results reveal that, compared to room temperature (294K), both the coupling strength (g) and the spring constant (α) of the spacer layer (Polyvinylpyrrolidone, PVP-40K) exhibit an increase of approximately 10% at 78K, indicating a temperature effect on vibration coupling. We also derived a theoretical formula that accurately describes the variation of coupling peaks with temperature, aligning well with the experimental data. This research provides valuable insights into the phonon transfer processes in nanomaterials at low temperatures.