Core Size Effect on the Vortex Quasiparticle Excitations in Overdoped $La_{2-x}Sr_xCuO_4$ Single Crystals

Liu, Z. Y.; Wen, H. H.; Xiang, T.; Komiya, Seiki; Sun, X. F.; Ando, Yoichi

Core Size Effect on the Vortex Quasiparticle Excitations in Overdoped $La_{2-x}Sr_xCuO_4$ Single Crystals

Authors

Description

Low temperature specific heat has been measured for an overdoped $La_{2-x}Sr_xCuO_4$ (x = 0.22) single crystal. The quasiparticle density of states (DOS) in the mixed state is found to deviate from the predicted scaling law $C_{vol}=Hf(T/H^{1/2})$. However, this scaling behavior is nicely reconciled if one considers the normal core region ($ξ\approx$ 21$Å$) which gives small contribution to the total DOS. The radius of the core and other parameters derived are consistent with reported values. Our results suggest that there is no zero-bias conductance peak (ZBCP), which is predicted by the simple Bogoliubov de-Gennes theory in the vortex core of a d-wave superconductor.
4 Pages, 4 Figures