Superatom orbitals of C60 on Ag(111): Two-photon photoemission and scanning tunneling spectroscopy
Superatom orbitals of C60 on Ag(111): Two-photon photoemission and scanning tunneling spectroscopy
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DOI：
10.1103/physrevb.84.195435
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发表时间：
2011-11-08
影响因子：
3.7
通讯作者：
Robey, S. W.
中科院分区：
文献类型：
--
作者：
Dutton, G. J.;Dougherty, D. B.;Robey, S. W.
用双光子光电子能谱(2PPE)和扫描隧道谱(STS)研究了Ag(111)表面C-60层的空位电子结构。除了为C-60单分子层提供未占据能级分配外，重点是在两种互补技术中识别C-60超原子分子轨道(SAMO)的特征，即被富勒烯壳层的球势弱束缚的漫射未占据能级。在2PPE中，S-SAMO位于费米能级以上3.3 eV，在STS中，偏置为3.5 eV。还讨论了p-SAMO能级对这两种测量技术的可能贡献。结果与最近的低温扫描隧道显微镜(LT-STM)研究C-60SAMOS在铜(111)和氧覆盖的铜(110)表面的工作进行了比较，并与以前对金(111)和铜(111)表面C-60单分子膜的2PPE测量结果进行了比较。
The unoccupied electronic structure of C-60 layers on Ag(111) was investigated with two-photon photoemission (2PPE) and scanning tunneling spectroscopy (STS). The focus, in addition to providing unoccupied level assignments for C-60 monolayers, is on identifying signatures of C-60 superatom molecular orbitals (SAMOs), diffuse unoccupied levels weakly bound by the spherical potential of the fullerene shell, in the two complementary techniques. The s-SAMO is identified 3.3 eV above the Fermi level in 2PPE and at a bias of 3.5 eV in STS. Possible contributions from p-SAMO levels are also discussed for both measurement techniques. The results are compared with recent low-temperature scanning tunneling microscopy (LT-STM) work that investigated C-60 SAMOs on Cu(111) and oxygen-covered Cu(110) surfaces and with previous 2PPE measurements for C-60 monolayers on Au(111) and Cu(111).