Quantum criticality stabilizes high T c superconductivity against competing symmetry-breaking instabilities

Josef Ashkenazi, Neil F. Johnson

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The occurrence of high-T c superconductivity in systems including the cuprates and the iron-based superconductors, is known to coincide with the existence of anomalous normal-state properties which have been associated with quantum criticality. We argue here that this observation results from the fact that quantum criticality can allow the occurrence of very-strong-coupling superconductivity by preventing its suppression due to competing symmetry-breaking instabilities. Treating the electrons through a large-U ansatz yields their separation into boson quasiparticles which are directly involved in the formation of these instabilities, represented as their Bose condensates, and charge-carrying fermion quasiparticles which are affected by them indirectly. Within the critical regime, condensates corresponding to the different broken-symmetry states are combined; consequently their negative effect on the pairing of the fermions is strongly diminished, enabling high-T c superconductivity to occur. The observed phase diagram of the hole-doped cuprates then derives from a hidden T=0 quantum phase transition between a Fermi-liquid and a non-Fermi-liquid broken-symmetry striped state. The pseudogap range within this diagram is found to include two distinct regimes, with partial pairing occurring in one of them. Conclusions are drawn concerning a strategy for searching for new high-T c systems with higher transition temperatures.

Original languageEnglish (US)
Pages (from-to)2611-2616
Number of pages6
JournalJournal of Superconductivity and Novel Magnetism
Issue number8
StatePublished - Aug 2013


  • Criticality
  • Cuprates
  • Instability
  • Mechanism
  • Pseudogap
  • Superconductivity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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