Electron Correlation and Charge Transfer in (Ba$_{0.9}$Nd$_{0.1})$CuO$_{2+\delta }$/(CaCuO$_{2})_{2 }$ Superconducting Superlattices

ORAL

Abstract

The mechanism of cuprate high-temperature superconductivity is still controversial. It is widely accepted that HTSC occurs primarily within CuO planes of cuprates, yet there is contention concerning the in-plane low-energy physics. Using 2$\times $2 high-Tc superlattices (SL) (Ba$_{0.9}$Nd$_{0.1}$CuO$_{2+x})_{2}$/(CaCuO$_{2})_{2}$, we probe the CuO$_{2}$ planes by applying x-ray emission/absorption spectroscopy. The pulsed-laser deposited SL consist of two separately insulating layers and exhibit a T$c$ of 80K. Superconductivity occurs exclusively within the infinite layer (IL) and not the charge reservoir (CR) of the SL. We demonstrate resonant x-ray emission and absorption to be insightful tools for studying the IL, CR and superlattice structures. We measure the O 1s density of state to be insulating for the component layers and metallic for the superlattice. Using resonant inelastic scattering (RIXS) we make the first direct observation of Zhang-Rice singlets in artificial high-Tc superconducting heteroepitaxial structures. A comparison of the x-ray emission spectra of the SL and its component layers gives evidence of charge transport from the so-called charge reservoir layer to the infinite layer.

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Authors

  • Byron Freelon

    LBNL

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston

  • Nilanjan Das

    Dept. of Physics, ESFM-IPN, Mexico City, Dept. of Physics, The University of Texas at El Paso, Texas A\&M University, Southeast Missouri State University, Departamento de Fisica, FCEN, Universidad de Buenos Aires, Nunez, Argentina, Cyclotron Institute, Texas A\&M University, University of Houston, Denison U., Advanced Space Propulsion Laboratory, AdAstra Rocket Company, Texas Tech University, Department of Chemistry and Biochemistry, Texas State Unv. - San Marcos, Department of Physics, Texas State Unv. - San Marcos, Rice U., Texas State University - San Marcos, Freescale Semiconductor, Inc., Varian Semiconductor Equipment Associates, Gloucester, MA, University of North Texas, Denton, TX, National Insitute of Standards \& Technology, Gaithersburg, MD, James Madison University, Harrisonburg, VA, Texas A\&M University, College Station, TX, Hong Kong University of Science and Technology; Texas Center for Superconductivity and Advanced Materials, University of Houston, Texas Center for Superconductivity at the University of Houston, University of Houston, University of Idaho, Department of Physics, Istanbul Technical University, University of California at Davis, Physics Department, University of South Florida, FL 33620, Physics Department, Texas A\&M University, TX 77843, Center for Studies in Statistical Mechanics and Complex Systems, The University of Texas at Austin, Rice University, TcSUH, University of Houston, Lawrence Berkeley National Laboratory, Hong Kong University of Science and Technology, Institute of Solid State Physics, Bulgarian Academy of Sciences, Hong Kong University of Science and Technology; Texas Center for Superconductivity, University of Houston; Lawrence Berkeley National Laboratory, Texas Center for Superconductivity, University of Houston