Study of La0.67Ca0.33MnO3(001) thin film surfacestructure using scanning tunneling microscopy

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 Mn-O terminated surface, insulating ( 2 × 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 ( 2 × 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.