Observation of second sound in a rapidly varying temperature field in Ge.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34193427.
- Also identified by DOI 10.1126/sciadv.abg4677 and PMC identifier 8245038.
- Licence recorded as CC BY-NC.
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Abstract
Second sound is known as the thermal transport regime where heat is carried by temperature waves. Its experimental observation was previously restricted to a small number of materials, usually in rather narrow temperature windows. We show that it is possible to overcome these limitations by driving the system with a rapidly varying temperature field. High-frequency second sound is demonstrated in bulk natural Ge between 7 K and room temperature by studying the phase lag of the thermal response under a harmonic high-frequency external thermal excitation and addressing the relaxation time and the propagation velocity of the heat waves. These results provide a route to investigate the potential of wave-like heat transport in almost any material, opening opportunities to control heat through its oscillatory nature.