Effect of controlled disorder on quasiparticle thermal transport in Bi2Sr2CaCu2O8 - art. no. 184509

Low-temperature thermal conductivity kappa of optimally doped Bi2Sr2CaCu2O8 was studied before and after the introduction of point defects by electron irradiation. The amplitude of the linear component of kappa remains unchan ged, confirming the universal nature of heat transport by zero-energy quasi particles. The induced decrease in the absolute value of kappa at finite te mperatures allows us to resolve a nonuniversal term in kappa due to conduct ion by finite-energy quasiparticles. The magnitude of this term provides an estimate of the quasiparticle lifetime at subkelvin temperatures.