Electronic inhomogeneity and band structure on superstructural CuO2 planes of infinite-layer Sr0.94La0.06CuO2+y films

Abstract

Scanning tunneling microscopy and spectroscopy are utilized to study the atomic-scale structure and electronic properties of infinite-layer Sr0.94La0.06CuO2+y films prepared on SrRuO3-buffered SrTiO3(001) substrate by ozone-assisted molecular beam epitaxy. Incommensurate structural supermodulation with a period of 24.5Å is identified on the CuO2-terminated surface, leading to characteristic stripes running along the 45o direction with respect to the Cu-O-Cu bonds. Spatially resolved tunneling spectra reveal substantial inhomogeneity on a nanometer length scale and emergence of in-gap states at sufficient doping. Despite the Fermi level shifting up to 0.7 eV, the charge-transfer energy gap of the CuO2 planes remains fundamentally unchanged at different doping levels. The occurrence of the CuO2 superstructure is constrained in the surface region and its formation is found to link with oxygen intake that serves as doping agent of holes in the epitaxial films.

5 pages, 4 figures, also see arXiv:1904.12280

References in corpus (5)

• Scanning tunneling spectroscopy of high-temperature superconductors
• Nodeless pairing in superconducting copper-oxide monolayer films on Bi2Sr2CaCu2O8+δ
• Nodeless superconductivity arising from strong (pi,pi) antiferromagnetism in the infinite-layer electron-doped cuprate Sr1-xLaxCuO2
• Atomic manipulation of the gap in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$
• Charge transfer gap for T'-RE2CuO4 and T-La2CuO4 as estimated from Madelung potential calculations

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