Location of gap nodes in the organic superconductors $\kappa$-(ET)${}_2$Cu(NCS)${}_2$ and $\kappa$-(ET)${}_2$Cu[N(CN)${}_2$]Br determined by magnetocalorimetry

Abstract

We report specific heat measurements of the organic superconductors $\kappa$-(ET)${}_2$Cu(NCS)${}_2$ and $\kappa$-(ET)${}_2$Cu[N(CN)${}_2$]Br. When the magnetic field is rotated in the highly conducting planes at low temperature ($T\simeq 0.4$ K), we observe clear oscillations of specific heat which have a strong fourfold component. The observed strong field and temperature dependence of this fourfold component identifies it as originating from nodes in the superconducting energy gap which point along the in-plane crystal axes ($d_{xy}$ symmetry)

Expanded version with additional experimental details (5 pages)

References in corpus (7)

• Specific heat measurements of the gap structure of the organic superconductors kappa-(ET)_2Cu[N(CN)_2]Br and kappa-(ET)_2Cu(NCS)_2
• Nodal structure of quasi-2D superconductors probed by magnetic field
• Pairing Symmetry Competition in Organic Superconductors
• Unconventional superconductors under rotating magnetic field II: thermal transport
• Thermal conductivity evidence for d_{x^2-y^2} pairing symmetry in the heavy-fermion CeIrIn5 superconductor
• Superconductor-Insulator Phase Separation Induced by Rapid Cooling in kappa-(ET)_2Cu[N(CN)_2]Br
• Inversion of specific heat oscillations with in-plane magnetic field angle in 2D d-wave superconductors

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