An Sr/Si（100）-c（2 ×4） surface is investigated by high-resolution scanning tunneling microscopy （STM） and scanning tunneling spectroscopy （STS）. The semiconductor property of this surface is confirmed by S...An Sr/Si（100）-c（2 ×4） surface is investigated by high-resolution scanning tunneling microscopy （STM） and scanning tunneling spectroscopy （STS）. The semiconductor property of this surface is confirmed by STS. The STM images of this surface shows that it is bias-voltage dependent and an atomic resolution image can be obtained at an empty state under a bias voltage of 1.5 V. Furthermore, one-dimensional （ID） diffusion of vacancies can be found in the room-temperature STM images. Sr vacancies diffuse along the valley channels, which are constructed by silicon dimers in the surface. Weak interaction between Sr and silicon dimers, low metal coverage, surface vacancy, and energy of thermal fluctuation at room temperature all contribute to this 1D diffusion.展开更多
Light-induced structural transformation of 4-(amyloxy)cinnamic acid (AOCA) on the surface of highly oriented pyrolytic graphite (HOPG) was investigated with scanning tunneling microscopy (STM). AOCA molecules form hig...Light-induced structural transformation of 4-(amyloxy)cinnamic acid (AOCA) on the surface of highly oriented pyrolytic graphite (HOPG) was investigated with scanning tunneling microscopy (STM). AOCA molecules form highly-ordered adlayer on HOPG spontaneously, stabilized by hydrogen bonding between neighboring molecules. After UV-light irradiation onto the adlayer, the ordered ad- layer was disrupted and a new disordered structure was observed, which indicated that dimerization of AOCA molecules took place. The STM results reveal the direct evidence for the photoisomerization of cin- namic acid at atom level.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 60771066)
文摘An Sr/Si（100）-c（2 ×4） surface is investigated by high-resolution scanning tunneling microscopy （STM） and scanning tunneling spectroscopy （STS）. The semiconductor property of this surface is confirmed by STS. The STM images of this surface shows that it is bias-voltage dependent and an atomic resolution image can be obtained at an empty state under a bias voltage of 1.5 V. Furthermore, one-dimensional （ID） diffusion of vacancies can be found in the room-temperature STM images. Sr vacancies diffuse along the valley channels, which are constructed by silicon dimers in the surface. Weak interaction between Sr and silicon dimers, low metal coverage, surface vacancy, and energy of thermal fluctuation at room temperature all contribute to this 1D diffusion.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 20121301）the National Key Project on Basic Research （Grant No. 2002CCA03100）.
文摘Light-induced structural transformation of 4-(amyloxy)cinnamic acid (AOCA) on the surface of highly oriented pyrolytic graphite (HOPG) was investigated with scanning tunneling microscopy (STM). AOCA molecules form highly-ordered adlayer on HOPG spontaneously, stabilized by hydrogen bonding between neighboring molecules. After UV-light irradiation onto the adlayer, the ordered ad- layer was disrupted and a new disordered structure was observed, which indicated that dimerization of AOCA molecules took place. The STM results reveal the direct evidence for the photoisomerization of cin- namic acid at atom level.
