Low-temperature electronic heat transport in La2-xSrxCuO4 single crystals: unusual low-energy physics in the normal and superconducting states.
The thermal conductivity kappa is measured in a series of La2-xSrxCuO4 (0 < or = x < or = 0.22) single crystals down to 90 mK to elucidate the evolution of the residual electronic thermal conductivity kappa(res), which probes the extended quasiparticle states in the d-wave gap. We found that kappa(res)/T grows smoothly, except for a 1/8 anomaly, above x approximately 0.05, and shows no discontinuity at optimum doping, indicating that the behavior of kappa(res)/T is not governed by the metal-insulator crossover in the normal state; as a result, kappa(res)/T is much larger than what the normal-state resistivity would suggest in the underdoped region, which highlights the peculiarities in the low-energy physics in the cuprates.
Takeya
J
J
Central Research Institute of Electric Power Industry, Komae, Tokyo 201-8511, Japan.
Ando
Yoichi
Y
Komiya
Seiki
S
Sun
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XF