Physics:Pomeranchuk cooling

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Short description: Physical phenomenon

Pomeranchuk cooling (named after Isaak Pomeranchuk) is the phenomenon in which liquid helium-3 will cool if it is compressed isentropically when it is below 0.3 K. This occurs because helium-3 has the unusual property that its solid state can have a higher entropy than its liquid state. The effect was first observed by Yuri Anufriev in 1965.[1] This can be used to construct a cryogenic cooler.[2]

In 2021 an analog effect has been observed on twisted bilayer graphene[3][4][5] and in TMDs[6]

References

  1. Lee, David M. (1 July 1997). "The extraordinary phases of liquid ${}^{3}$He". Reviews of Modern Physics 69 (3): 645–666. doi:10.1103/RevModPhys.69.645. 
  2. Weisstein, Eric. "Pomeranchuk Cooling". http://scienceworld.wolfram.com/physics/PomeranchukCooling.html. 
  3. "Electrons in twisted graphene 'freeze' when heated" (in en-GB). 2021-04-21. https://physicsworld.com/electrons-in-twisted-graphene-freeze-when-heated/. 
  4. Rozen, Asaf; Park, Jeong Min; Zondiner, Uri; Cao, Yuan; Rodan-Legrain, Daniel; Taniguchi, Takashi; Watanabe, Kenji; Oreg, Yuval et al. (April 2021). "Entropic evidence for a Pomeranchuk effect in magic-angle graphene" (in en). Nature 592 (7853): 214–219. doi:10.1038/s41586-021-03319-3. ISSN 1476-4687. PMID 33828314. https://www.nature.com/articles/s41586-021-03319-3. 
  5. Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Aliberti, R.; Amoroso, A.; An, Q. et al. (November 2021). "Oscillating features in the electromagnetic structure of the neutron" (in en). Nature Physics 17 (11): 1200–1204. doi:10.1038/s41567-021-01345-6. ISSN 1745-2481. https://www.nature.com/articles/s41567-021-01345-6. 
  6. Li, Tingxin; Jiang, Shengwei; Li, Lizhong; Zhang, Yang; Kang, Kaifei; Zhu, Jiacheng; Watanabe, Kenji; Taniguchi, Takashi et al. (September 2021). "Continuous Mott transition in semiconductor moiré superlattices" (in en). Nature 597 (7876): 350–354. doi:10.1038/s41586-021-03853-0. ISSN 1476-4687. PMID 34526709. https://www.nature.com/articles/s41586-021-03853-0.