Pressure-induced unconventional superconductivity near a quantum critical point in CaFe2As2

Shinji Kawasaki, T. Tabuchi, X. F. Wang, X. H. Chen, Guo-Qing Zheng

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

75As-zero-field nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements are performed on CaFe2As 2 under pressure. At P = 4.7 and 10.8kbar, the temperature dependencies of nuclear-spin-lattice relaxation rate (1/T1) measured in the tetragonal phase show no coherence peak just below Tc(P) and decrease with decreasing temperature. The superconductivity is gapless at P = 4.7kbar but evolves to that with multiple gaps at P = 10.8kbar. We find that the superconductivity appears near a quantum critical point under pressures in the range 4.7kbar ≤ P ≤ 10.8kbar. Both electron correlation and superconductivity disappear in the collapsed tetragonal phase. A systematic study under pressure indicates that electron correlations play a vital role in forming Cooper pairs in this compound.

Original languageEnglish
Article number054004
JournalSuperconductor Science and Technology
Volume23
Issue number5
DOIs
Publication statusPublished - 2010

Fingerprint

Superconductivity
Electron correlations
critical point
superconductivity
Nuclear quadrupole resonance
nuclear quadrupole resonance
Spin-lattice relaxation
spin-lattice relaxation
nuclear spin
electrons
Nuclear magnetic resonance
Temperature
nuclear magnetic resonance
temperature

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Ceramics and Composites
  • Materials Chemistry
  • Metals and Alloys

Cite this

Pressure-induced unconventional superconductivity near a quantum critical point in CaFe2As2. / Kawasaki, Shinji; Tabuchi, T.; Wang, X. F.; Chen, X. H.; Zheng, Guo-Qing.

In: Superconductor Science and Technology, Vol. 23, No. 5, 054004, 2010.

Research output: Contribution to journalArticle

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