Thermal conductivity of unconventional superconductors in the vortex state

Thermal conductivity and gap structure of the superconducting phases of UPt3

“…6 we show the measured dκ/dT at T c as a function of the magnetic field, normalized to the normal state values : (dκ s /dT −dκ n /dT )/(κ n /T c (B)), where the subscript s means approaching T c from the superconducting state, and n from the normal state. As already mentioned [25,26] and shown by the measurements of Behnia et al [3,4] in UPt 3 , the slope dκ s /dB, and therefore also dκ s /dT, depends on the direction of current and field, and is related to the gap structure. Therefore, if the topology of the gap changes when passing from the high temperature low field A phase to the low temperature high field C phase, a jump of dκ/dT should be observed at the A→C phase transition.…”

“…In the literature (see Refs. [3,4,25,26] for the discussion of UPt 3 ), it is generally the jump in dκ/dB which is discussed. We have measured dκ/dT because our resolution for temperature scans was much better than for field scans, but the main conclusions should remain the same.…”

“…We discuss extensively our zero field data, and also present new measurements under magnetic fields. Measurements under field in the mixed state give an additional means of probing the gap structure [3,4,[24][25][26]. Indeed, the possibility of a hybrid gap such as that in the E 1g and E 2u models was proposed by Yin and Maki [25] on the basis of the mixed state thermal conductivity data of Behnia et al [3,4].…”

Relation between vortex excitation and thermal conductivity in superconductors

“…So far, the thermal conductivity in the vortex state has been investigated by the theory of gapless superconductors at high field [9,10], or the theory considering vortices as scattering centers [11]. Recently, the thermal conductivity in the vortex state of high-T c superconductors attracts much attention, because the quasiparticle states are qualitatively different in the vortex state between the d-wave pairing case and the conventional s-wave pairing cases.…”