Superconducting Density of States from the Magnetic Penetration Depth of Electron-Doped Cuprates La_{2-x}Ce_xCuO_{4-y} and Pr_{2-x}Ce_xCuO_{4-y}

John A. Skint; Mun-Seog Kim; Thomas R. Lemberger; T. Greibe; M. Naito

paper

Superconducting Density of States from the Magnetic Penetration Depth of Electron-Doped Cuprates La_{2-x}Ce_xCuO_{4-y} and Pr_{2-x}Ce_xCuO_{4-y}

arXiv:cond-mat/0301174

Abstract

From measurements of the magnetic penetration depth, $λ (T)$ , from 1.6 K to $T_{c}$ in films of electron-doped cuprates La $_{2 - x}$ Ce $_{x}$ CuO $_{4 - y}$ and Pr $_{2 - x}$ Ce $_{x}$ CuO $_{4 - y}$ we obtain the normalized density of states, $N_{s} (E)$ at T=0 by using a simple model. In this framework, the flat behavior of $λ^{- 2} (T)$ at low $T$ implies $N_{s} (E)$ is small, possibly gapped, at low energies. The upward curvature in $λ^{- 2} (T)$ near $T_{c}$ seen in overdoped films implies that superfluid comes from an anomalously small energy band within about $3 k_{B} T_{c}$ of the Fermi surface.

6 pages, 4 figures