Atomic-resolution two-dimensional mapping of holes in the cuprate superconductor La2−xSrxCuO4±δ

Abstract

One of the key factors in understanding high-Tc cuprate superconductors is the spatial distribution of holes in the sample. Since x-ray absorption spectroscopy (XAS) and electron-energy-loss spectroscopy (EELS) can directly measure the unoccupied 2p states of the oxygen, many experiments have already been performed for a wide range of doping conditions. While polarization-dependent x-ray fluorescence yield absorption cannot spatially resolve different oxygen sites, EELS combined with scanning transmission electron microscopy has the ability to resolve them with atomic resolution. However, since cuprate superconductors are extremely sensitive to electron irradiation, it has not been possible, to date, to characterize them with atomic resolution. Here, we succeeded in atomic-resolution two-dimensional mapping of holes in La2−xSrxCuO4±δ by overcoming the problem of irradiation damage using an advanced integration technique. In addition, we have demonstrated the anisotropic chemical bond related to the difference between px and py orbitals was observed with atomic resolution. The present approach enables atomic-resolution anisotropic spectroscopy and is expected to give information complementary to the polarization-dependent XAS.

Source-reported materials — not catalogue approval

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