Anomalous Thermal Diffusivity in Underdoped YBa${}_2$Cu${}_3$O${}_{6+x}$

J. -C. Zhang, E. M. Levenson-Falk, B. J. Ramshaw +5

We present local optical measurements of thermal diffusivity in the $ab$ plane of underdoped YBCO crystals. We find that the diffusivity anisotropy is comparable to reported values…