論文
放射光励起高分解能角度分解光電子分光による金属表面上の1次元電子状態の研究
2004 年 25 巻 8 号 p. 478-484
詳細
2004 年 25 巻 8 号 p. 478-484
Surface electronic states of a stepped Cu(755) surface were studied by angle-resolved ultraviolet photoelectron spectroscopy using synchrotron radiation (SR-ARUPS). We have observed an isotropic free-electron-like surface state below the Fermi level. Unlike to the stepped Ni(755) surface with the same surface structure, no electronic state localized at the step edges was found. This experimental fact shows that the valence-band structure plays an important role in inducing step-localized states. In addition, we tried to prepare Co atomic chains on the stepped Cu(755) surface by vacuum deposition. However, the analysis of low-electron-energy-diffraction (LEED) patterns shows that the Co atoms grow in island-growth mode into epitaxial triangular nanoislands. The Co electronic structure in these Co nanoislands is investigated also by SR-ARUPS. Below 0.2 ML, two Co-derived zero-dimensional peaks were clearly resolved at around 0.3 and 1.1 eV. With coverage increasing, these peaks shift toward each other. This peak shift dependent on the Co coverage is explained in terms of the enhanced exchange splitting that is caused to reduce unavoidably increased Coulomb interaction between Co electrons with flat-band localized in thesmall Co nanoislands at low coverages.
