Interface Superconductivity in Cuprates Defies Fermi-Liquid Description
- 192 Downloads
La2−x Sr x CuO4/La2CuO4 bilayers show interface superconductivity that originates from accumulation and depletion of mobile charge carriers across the interface. Surprisingly, the doping level can be varied broadly (within the interval 0.15<x<0.47) without affecting the transition temperature, which stays essentially constant and equal to that in optimally doped material, T c ≈ 40 K. We argue that this finding implies that doping up to the optimum level does not shift the chemical potential, unlike in ordinary Fermi liquids. We discuss possible physical scenarios that can give doping-independent chemical potential in the pseudogap regime: electronic phase separation, formation of charge density waves, strong Coulomb interactions, or self-trapping of mobile charge carriers.
KeywordsHigh-temperature superconductors Interface superconductivity Chemical potential Fermi liquid
The experimental work was done by J.W., A.T.B. and I.B. at BNL and was supported by the U.S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division. I.B. was supported in part by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF4410. Z.R. and M.V. were supported by the Serbian Ministry of Science, Project No. 171027.
- 9.Smadici, S., Lee, J.C.T., Wang, S., Abbamonte, P., Logvenov, G., Gozar, A., Deville Cavellin, C., Bozovic, I.: Superconducting transition at 38 K in insulating-overdoped La2CuO4- La1.64Sr0.36CuO4 superlattices: evidence for interface electronic redistribution from resonant soft X-ray scattering. Phys. Rev. Lett. 102, 107004 (2009)ADSCrossRefGoogle Scholar
- 18.Božović, I., He, X., Wu, J., Bollinger, A.T.: Dependence of critical temperature in overdoped copper oxides on superfluid density. Nature (2016). in pressGoogle Scholar
- 28.Zhou, W., Xing, X.Z., Zhao, H.J., Shi, Z.X., Yamaura, K.: Anomalous carrier density independent superconductivity in iron pnictides. arXiv:1604.02839v1 (2016)