Angular Position of Nodes in the Superconducting Gap of Quasi-2D Heavy-Fermion SuperconductorCeCoIn5

Abstract

The thermal conductivity of the heavy-fermion superconductor CeCoIn5 has been studied in a magnetic field rotating within the 2D planes. A clear fourfold symmetry of the thermal conductivity which is characteristic of a superconducting gap with nodes along the ( +/- pi,+/- pi) directions is resolved. The thermal conductivity measurement also reveals a first-order transition at H(c2), indicating a Pauli limited superconducting state. These results indicate that the symmetry most likely belongs to d(x(2)-y(2)), implying that the anisotropic antiferromagnetic fluctuation is relevant to the superconductivity.

Gap symmetry of superconducting borocarbide YNi2B2C and skutterudite PrOs4Sb12

“…The associated magnetothermal conductivity provides a unique window to investigate nodal structures of ∆(k) . In this way Izawa et al have succeeded in identifying the gap symmetry of Sr 2 RuO 4 , CeCoIn 5 and κ-(ET) 2 Cu(NCS) 2 [5,6,7]. More recently the magnetothermal conductivity data from YNi 2 B 2 C and PrOs 4 Sb 12 has revealed the presence of point nodes in ∆(k) [8,11].…”

“…As is readily seen the φ-dependence of the thermal conductivity is adequate to identify one of four ∆(k) gap functions we have considered sofar. In this way ∆(k) in Sr 2 RuO 4 [5], CeCoIn 5 [6] and κ-(ET) 2 Cu(NCS) 2 [7] are identified. On the other hand the φ-dependence of κ xx and κ xy in YBCO so far determined [30,32,33] do not match the one for d x 2 −y 2 -wave.…”

“…Indeed Izawa et al have shown f-wave sc in Sr 2 RuO 4 [5], d-wave sc in CeCoIn 5 [6] and κ-(ET) 2 Cu(NCS) 2 [7] through the angle dependent magnetothermal conductivity. More recently gap functions ∆(k) in borocarbide YNi 2 B 2 C and skutterudite PrOs 4 Sb 12 are shown to have point nodes and described in terms of s+g-wave sc [8][9][10][11][12].…”

Unconventional superconductivity in the strong-coupling limit for the heavy fermion system CeCoIn5

“…The error in determining these magnitudes is within the size of the points. The bubble-gum-pink line is a fit to the gap data with the nodal BCS gap temperature-evolution ∆(T ) = ∆(0) 1 − (T/T * ) 3 . Insert: temperature-evolution of the constant normal channel.…”

Analysis of Magnetic Field-Angle Dependent Electronic Raman Scattering to Probe the Superconducting Gap

“…The field-angle dependent specific heat and thermal conductivity experiments have been studied to probe superconducting pairing symmetry in novel materials, such as a family of heavy-fermion compounds CeM In 5 (M = Rh, Co, and Ir) [2][3][4]. Fig.…”