Electron quadruplets
The condensate of electron quadruplets is a proposed state of matter in which Cooper pairs are formed but do not exhibit long-range order, but electron quadruplets do. Such states emerge in systems with multiple broken symmetries due to the partial melting of the underlying low-temperature order, which destroys the condensates of Cooper pairs but preserves the condensates formed by pairs of preformed fermion pairs.[1][2] One example of the proposed electron quadruplet condensates is charge-4e superconductivity first proposed by Berg, Fradkin and Kivelson.[3] Another example is "quartic metal" phase [4][5] is related to but distinct from those superconductors explained by the standard BCS theory; rather than expelling magnetic field lines as in the Meissner effect, it generates them, a spontaneous Nernst effect that indicates the breaking of time-reversal symmetry.[6]
Related states can form in pair-density-wave systems.[7] In systems with a greater number of broken symmetries, theoretical studies have demonstrated the existence of charge-6e and more complex orders.[8][9] After the theoretical possibility was raised, observations consistent with electron quadrupling were published using hole-doped Ba1-xKxFe2As2 in 2021,[6][10] with evidence of vestigial quadrupling reported in CsV3Sb5 soon after, in early 2022.[11]
See also
[edit]References
[edit]- ^ Babaev, Egor; Sudbø, Asle; Ashcroft, N. W. (October 2004). "A superconductor to superfluid phase transition in liquid metallic hydrogen". Nature. 431 (7009): 666–668. arXiv:cond-mat/0410408. Bibcode:2004Natur.431..666B. doi:10.1038/nature02910. ISSN 1476-4687. PMID 15470422.
- ^ Smiseth, J.; Smørgrav, E.; Babaev, E.; Sudbø, A. (6 June 2005). "Field- and temperature-induced topological phase transitions in the three-dimensional N -component London superconductor". Physical Review B. 71 (21). arXiv:cond-mat/0411761. doi:10.1103/PhysRevB.71.214509.
- ^ Berg, Erez; Fradkin, Eduardo; Kivelson, Steven A. (November 2009). "Charge-4e superconductivity from pair-density-wave order in certain high-temperature superconductors". Nature Physics. 5 (11): 830–833. arXiv:0904.1230. Bibcode:2009NatPh...5..830B. doi:10.1038/nphys1389. ISSN 1745-2481.
- ^ Bojesen, Troels Arnfred; Babaev, Egor; Sudbø, Asle (2013-12-30). "Time reversal symmetry breakdown in normal and superconducting states in frustrated three-band systems". Physical Review B. 88 (22): 220511. arXiv:1306.2313. Bibcode:2013PhRvB..88v0511B. doi:10.1103/PhysRevB.88.220511.
- ^ Bojesen, Troels Arnfred; Babaev, Egor; Sudbø, Asle (2014-03-11). "Phase transitions and anomalous normal state in superconductors with broken time-reversal symmetry". Physical Review B. 89 (10): 104509. arXiv:1401.5802. Bibcode:2014PhRvB..89j4509B. doi:10.1103/PhysRevB.89.104509.
- ^ a b Grinenko, Vadim; Weston, Daniel; Caglieris, Federico; Wuttke, Christoph; Hess, Christian; Gottschall, Tino; Maccari, Ilaria; Gorbunov, Denis; Zherlitsyn, Sergei; Wosnitza, Jochen; Rydh, Andreas; Kihou, Kunihiro; Lee, Chul-Ho; Sarkar, Rajib; Dengre, Shanu; Garaud, Julien; Charnukha, Aliaksei; Hühne, Ruben; Nielsch, Kornelius; Büchner, Bernd; Klauss, Hans-Henning; Babaev, Egor (2021-10-18). "State with spontaneously broken time-reversal symmetry above the superconducting phase transition". Nature Physics. 17 (11): 1254–1259. arXiv:2103.17190. Bibcode:2021arXiv210317190G. doi:10.1038/s41567-021-01350-9. ISSN 1745-2481. S2CID 235732434.
- ^ Agterberg, D. F.; Tsunetsugu, H. (August 2008). "Dislocations and vortices in pair-density-wave superconductors". Nature Physics. 4 (8): 639–642. doi:10.1038/nphys999.
- ^ Herland, Egil V.; Babaev, Egor; Sudbø, Asle (8 October 2010). "Phase transitions in a three dimensional U ( 1 ) × U ( 1 ) lattice London superconductor: Metallic superfluid and charge- 4 e superconducting states". Physical Review B. 82 (13). arXiv:1006.3311. doi:10.1103/PhysRevB.82.134511.
- ^ Agterberg, D. F.; Geracie, M.; Tsunetsugu, H. (26 July 2011). "Conventional and charge-six superfluids from melting hexagonal Fulde-Ferrell-Larkin-Ovchinnikov phases in two dimensions". Physical Review B. 84 (1). arXiv:1106.1685. doi:10.1103/PhysRevB.84.014513.
- ^ "Superconductor reveals new state of matter involving pairs of Cooper pairs". Physics World. 2021-11-03. Retrieved 2021-11-06.
- ^ "Charge-4𝑒 and Charge-6𝑒 Flux Quantization and Higher Charge Superconductivity in Kagome Superconductor Ring Devices". Physical Review X. 89 (14): 021025. arXiv:2201.10352.
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