摘要
利用第一性原理方法模拟了自由钒氧酞菁 (VOPc)和钒酞菁 (VPc)分子的扫描隧道显微镜 (STM)图像 ,与实验观察结果相当符合 .理论STM图像都显示出亚分子内结构 ,外围呈四叶状 .其主要差异表现在VOPc分子中心处的钒氧离子在STM图像中为一空洞 ,而在VPc分子的STM图像中钒离子为突起的亮斑 .通过分析VOPc和VPc分子的电子结构 ,对模拟结果给出自洽的理论解释 .造成两者图像显著不同的物理原因是VPc分子在费米能级附近有明显含dz2 成分的分子轨道 ,导致钒离子在STM图像中央为突起的亮斑 .而在VOPc分子中dz2 分态密度峰位由于氧原子的加入使之远离费米能级 ,使STM不能“看到”VOPc分子中钒氧离子 .
We presented the simulated scanning tunneling microscope (STM) images of vanadyl phthalocyanine (VOPc) and vanadium phthalocyanine (VPc) molecules as well as their electronic structures obtained by using the first-principles method. The simulated STM images show submolecular structures and four-leaves at its periphery, and well reproduce the features of the experimental images. The main difference between the two molecules is that the central vanadium ion in VPc appears as a bright bump in the molecular image, while there is a hole at the centre of the molecular STM image in VOPc. The simulated images are interpreted by that VPc molecule has significant d z 2 character near the Fermi level, while the dark central region is attributed to the oxygen atom causing the d z 2 states far away from Fermi level in VOPc molecule.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第3期609-615,共7页
Acta Physica Sinica
基金
王宽诚博士后奖励基金
国家自然科学基金 (批准号 :10 0 740 5 8)
国家自然科学杰出青年科学基金 (批准号 :2 0 0 2 5 30 9)资助的课题~~
