论文标题
电子不均匀性和频带结构在无限层SR0.94LA0.06CUO2+y胶片的上层结构CUO2平面上
Electronic inhomogeneity and band structure on superstructural CuO2 planes of infinite-layer Sr0.94La0.06CuO2+y films
论文作者
论文摘要
扫描隧道显微镜和光谱学用于研究无限 - 层SR0.94LA0.06CUO2+Y膜在Srruo3-buffered Srtio3（001）底物上制备的胶片的原子尺度结构和电子性能。在CUO2端端的表面上鉴定出24.5Å的不可固定的结构超调制，从而导致相对于Cu-O-CU键沿45O方向延伸的特征条纹。空间分辨的隧道光谱在纳米长度尺度上显示出很大的不均匀性，并在足够的掺杂时出现间隙状态。尽管费米水平升至0.7 eV，但CuO2平面的电荷转移能量差距在不同的掺杂水平上从根本上保持不变。 CUO2上层建筑的发生在表面区域受到限制，并发现其形成与氧气摄入量相关，后者是外在膜中孔的掺杂剂。
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.
