Persistence of Li Induced Kondo Moments in the Superconducting State of Cuprates

J. Bobroff; H. Alloul; W. A. MacFarlane; P. Mendels; N. Blanchard; G. Collin; J.-F. Marucco

doi:10.1103/PhysRevLett.86.4116

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Persistence of Li Induced Kondo Moments in the Superconducting State of Cuprates

J. Bobroff, H. Alloul, W. A. MacFarlane, P. Mendels, N. Blanchard, G. Collin, J.-F. Marucco

DOI 10.1103/PhysRevLett.86.4116 · Physical Review Letters

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Abstract

Using 7Li NMR shift data, the anomalous local moment induced by spinless Li impurities persists below Tc in YBa2Cu3O6+y. In the underdoped regime, the moments retain their Curie law below Tc. In contrast, near optimal doping, the large Kondo screening observed above Tc (TK=135K) is strongly reduced below Tc as expected theoretically when the superconducting gap develops. The limited spatial extent of the induced moment (on first near neighbor Cu) is not drastically modified below Tc, which allows a comparison with STM determination of the local density of states. Our results constrain theoretical models of the impurity electronic properties.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O6+y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
YBa2Cu3O6.97 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	85.3	Pressure not reported	unknown
YBa2Cu3O6.6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	41	Pressure not reported	unknown