In their comment [X. F. Sun and Yoichi Ando, preceding paper, Phys. Rev. B79, 176501 (2009)] on our study of phonon heat transport in ${\text{Nd}}_2{\text{CuO}}_4$ [S. Y. Li, J.-B. Bonnemaison, A. Payeur, P. Fournier, C. H. Wang, X. H. Chen, and Louis Taillefer, Phys. Rev. B 77, 134501 (2008)], Sun and Ando estimate that the phonon mean free path at low temperature is roughly half the width of the single crystal used in our study, from which they argue that phonon scattering cannot be dominated by sample boundaries. Here we show that their use of specific-heat data on ${\text{Nd}}_2{\text{CuO}}_4$, which contains a large magnetic contribution at low temperature that is difficult to reliably extract, leads to an underestimate of the mean free path by a factor 2 compared to an estimate based on the specific-heat data of the nonmagnetic isostructural analog ${\text{Pr}}_2{\text{CuO}}_4$. This removes the apparent contradiction raised by Sun and Ando.

• Received 20 November 2008

DOI:https://doi.org/10.1103/PhysRevB.79.176502