Thermal conductivity across the phase diagram of cuprates: Low-energy quasiparticles and doping dependence of the superconducting gap

Mike Sutherland; D. G. Hawthorn; R. W. Hill; F. Ronning; S. Wakimoto; H. Zhang; C. Proust; Etienne Boaknin; C. Lupien; Louis Taillefer; Ruixing Liang; D. A. Bonn; W. N. Hardy; Robert Gagnon; N. E. Hussey; T. Kimura; M. Nohara; H. Takagi

doi:10.1103/PhysRevB.67.174520

Thermal conductivity across the phase diagram of cuprates: Low-energy quasiparticles and doping dependence of the superconducting gap

Mike Sutherland, D. G. Hawthorn, R. W. Hill, F. Ronning, S. Wakimoto, H. Zhang, C. Proust, Etienne Boaknin, C. Lupien, Louis Taillefer, Ruixing Liang, D. A. Bonn, W. N. Hardy, Robert Gagnon, N. E. Hussey, T. Kimura, M. Nohara, H. Takagi

DOI 10.1103/PhysRevB.67.174520 · Physical Review B

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Abstract

Heat transport in the cuprate superconductors YBa2Cu3Oy and La2−xSrxCuO4 was measured at low temperatures as a function of doping. A residual linear term κ0/T is observed throughout the superconducting region and it decreases steadily as the Mott insulator is approached from the overdoped regime. The low-energy quasiparticle gap extracted from κ0/T is seen to scale closely with the pseudogap. The ubiquitous presence of nodes and the tracking of the pseudogap shows that the overall gap remains of the pure d-wave form throughout the phase diagram, which excludes the possibility of a complex component (ix) appearing at a putative quantum phase transition and argues against a nonsuperconducting origin to the pseudogap. A comparison with superfluid density measurements reveals that the quasiparticle effective charge is weakly dependent on doping and close to unity.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	89	Pressure not reported	zero_resistance
YBa2Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	62	Pressure not reported	zero_resistance
YBa2Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	44	Pressure not reported	zero_resistance
YBa2Cu3Oy Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	93.5	Pressure not reported	zero_resistance
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	5.5	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8.5	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	19	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	16	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	34	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	33.5	Pressure not reported	unknown