Autor: |
Tajik, M., Witte, T., Brand, Ch., Rettig, L., Sothmann, B., Bovensiepen, U., von Hoegen, M. Horn |
Rok vydání: |
2023 |
Předmět: |
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Druh dokumentu: |
Working Paper |
Popis: |
In this work, we study the heat transfer from electron to phonon system within a five monolayer thin epitaxial Pb film on Si(111) upon fs-laser excitation. The response of the electron system is determined using time-resolved photoelectron spectroscopy while the lattice excitation is measured by means of the Debye-Waller effect in time-resolved reflection high-energy electron diffraction. The electrons lose their heat within 0.5 ps while the lattice temperature rises slowly in 3.5 to 8 ps, leaving a gap of 3-7 ps. We propose that the hidden energy is transiently stored in high-frequency phonon modes for which diffraction is insensitive and which are excited in 0.5 ps. Within a three-temperature model we use three heat baths, namely electrons, high-frequency and low-frequency phonon modes to simulate the observations. The excitation of low-frequency acoustic phonons, i.e., thermalization of the lattice is facilitated through anharmonic phonon-phonon interaction. |
Databáze: |
arXiv |
Externí odkaz: |
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