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

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  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". Eric Weisstein's World of Science.
  3. ^ "Electrons in twisted graphene 'freeze' when heated". Physics World. 2021-04-21. Retrieved 2021-11-21.
  4. ^ Rozen, Asaf; Park, Jeong Min; Zondiner, Uri; Cao, Yuan; Rodan-Legrain, Daniel; Taniguchi, Takashi; Watanabe, Kenji; Oreg, Yuval; Stern, Ady; Berg, Erez; Jarillo-Herrero, Pablo (April 2021). "Entropic evidence for a Pomeranchuk effect in magic-angle graphene". Nature. 592 (7853): 214–219. arXiv:2009.01836. doi:10.1038/s41586-021-03319-3. ISSN 1476-4687. PMID 33828314. S2CID 221516628.
  5. ^ Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.; Albrecht, M.; Aliberti, R.; Amoroso, A.; An, Q.; Lavania, Anita; Bai, X. H.; Bai, Y. (November 2021). "Oscillating features in the electromagnetic structure of the neutron". Nature Physics. 17 (11): 1200–1204. arXiv:2103.12486. doi:10.1038/s41567-021-01345-6. ISSN 1745-2481. S2CID 243888280.
  6. ^ Li, Tingxin; Jiang, Shengwei; Li, Lizhong; Zhang, Yang; Kang, Kaifei; Zhu, Jiacheng; Watanabe, Kenji; Taniguchi, Takashi; Chowdhury, Debanjan; Fu, Liang; Shan, Jie; Mak, Kin Fai (September 2021). "Continuous Mott transition in semiconductor moiré superlattices". Nature. 597 (7876): 350–354. arXiv:2103.09779. doi:10.1038/s41586-021-03853-0. ISSN 1476-4687. PMID 34526709. S2CID 232257656.