中文摘要：

利用Scanning Tunneling Microscope（STM）和Scanning Tunneling Spectroscopy（STS）技术研究了La0.67Ca0.33MnO3（001）表面性质,研究发现表面呈现多相分离现象,在锰氧终端面观察到了绝缘性的（槡2×槡2）R45°重构表面和金属性的（1×1）重构表面,在镧钙氧终端面,观察到了表面呈现条纹状结构.La0.67Ca0.33MnO3（001）面（槡2×槡2）R45°重构表面电子态随温度的演化,表明（槡2×槡2）R45°重构作为一个绝缘相稳定在表面,可能掩盖了体相中相变信息.

英文摘要：

La0.67Ca0.33MnO3（001） thin films have been grown with pulsed laser deposition method,and the surface structures and electronic states have been characterized using scanning tunneling microscopy /spectroscopy（STM/STS）.In the MnO terminated surface,insulating（21/2×21/2） R45° reconstruction surface and metallic（1 × 1） reconstruction surface are observed.In the（La,Ca）-O terminated surface,the surface presents the stripe structure.The results obtained from the variable temperature STM /STS show that the（21/2 × 21/2） R45° reconstructed surface persists in insulating phase in a temperature range of 144—300 K,which may shield the signal of possible insulator-metal transition occurred in bulk in STS measurements.