Bulk superconductivity in undoped T'-La${}_{1.9}$Y${}_{0.1}$CuO${}_4$ probed by muon spin rotation

Abstract

The Meissner effect has been directly demonstrated by depth-resolved muon spin rotation measurements in high-quality thin films of the T'-structured cuprate, T'-La${}_{1.9}$Y${}_{0.1}$CuO${}_4$, to confirm bulk superconductivity ($T_c\simeq 21$ K) in its {\sl undoped} state. The gradual expelling of an external magnetic field is observed over a depth range of $\sim$100 nm in films with a thickness of 275(15) nm, from which the penetration depth is deduced to be 466(22) nm. Based on this result, we argue that the true ground state of the "parent" compound of the $n$-type cuprates is not a Mott insulator but a strongly correlated metal with colossal sensitivity to apical oxygen impurities.

5 pages, 4 figures

References in corpus (2)

• Crystal structure and high-field magnetism of La2CuO4
• The Meissner effect in a strongly underdoped cuprate above its critical temperature

Cited by in corpus (4)

• Novel Electronic State and Superconductivity in the Electron-Doped High-Tc T'-Superconductors
• Pairing Symmetry Studied from Impurity Effects in the Undoped Superconductor T'-La${}_{1.8}$Eu${}_{0.2}$CuO${}_4$
• Magnetism behavior of $T^{\prime }$-type Eu${}_2$CuO${}_4$ revealed by muon spin rotation/relaxation measurements
• Eliashberg analysis of the optical conductivity in superconducting Pr${}_2$CuO${}_x$ ($x\simeq 4$)