Fuchigami K, Gai Z, Ward T Z, Yin L F, Snijders P C, Plummer E W, Shen J
Materials Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2009 Feb 13;102(6):066104. doi: 10.1103/PhysRevLett.102.066104.
We studied the surface structure of La_{5/8}Ca_{3/8}MnO_{3}(001) thin films using in situ scanning tunneling microscopy (STM). Atomically resolved STM images reveal that a (sqrt[2]xsqrt[2])R45;{ degrees } reconstructed surface and a (1x1) surface can be converted back and forth through adsorption and desorption of oxygen at the surface. The electrical properties of the surfaces are investigated by scanning tunneling spectroscopy. I-V curves clearly show that the presence of an oxygen overlayer renders the surface insulating while the (1x1) surface without the oxygen overlayer is metallic.
我们使用原位扫描隧道显微镜（STM）研究了La_{5/8}Ca_{3/8}MnO_{3}(001)薄膜的表面结构。原子分辨的STM图像显示，通过表面氧的吸附和解吸，(√2×√2)R45°重构表面和(1×1)表面可以相互转换。通过扫描隧道谱研究了表面的电学性质。I-V曲线清楚地表明，氧覆盖层的存在使表面绝缘，而没有氧覆盖层的(1×1)表面是金属性的。
