In a recent Letter [J. K. Dong et al., Phys. Rev. Lett. 104, 087005 (2010)], Dong \textit{et al}. have observed a T1.5 dependence of resistivity ρ in KFe2As2 at the upper critical field Bc2 = 5 T parallel to the c axis and have suggested the existence of a field-induced quantum critical point (QCP) at Bc2. In this comment, we argue that observation of a T1.5 dependence of ρ in a sample showing broad resistive transitions does not constitute evidence for a QCP and that recent dHvA results do not support the proposed QCP.
@article{arxiv.1005.3868,
title = {Comment on "Quantum Criticality and Nodal Superconductivity in the FeAs-Based Superconductor KFe$_2$As$_2$"},
author = {Taichi Terashima and Motoi Kimata and Nobuyuki Kurita and Hidetaka Satsukawa and Atsushi Harada and Kaori Hazama and Motoharu Imai and Akira Sato and Kunihiro Kihou and Chul-Ho Lee and Hijiri Kito and Hiroshi Eisaki and Akira Iyo and Taku Saito and Hideto Fukazawa and Yoh Kohori and Hisatomo Harima and Shinya Uji},
journal= {arXiv preprint arXiv:1005.3868},
year = {2010}
}
Comments
3 pages, 2 figures + 1 supplemental figure, to be published in PRL