LnCu2O4(Ln=Gd,Nd)电子结构的XPS研究

用XPS测定了LnCu2O4(Ln=Gd, Nd)的内层和价层电子能谱,观察到LnCu2O4中稀土金属的3d电子结合能比相应的稀土金属简单氧化物的3d结合能低0.8～0.9 eV,而Cu的2p电子结合能比CuO的高0.4～0.5 eV,因此推断在LnCu2O4的Ln－O－Cu链中存在Cu→O→Ln电荷转移.XPS分析还表明LnCu2O4的Cu原子上有较低的电荷密度,但不存在混合价态.此外,通过比较价电子能谱,发现NdCu2O4的Ln 4f Cu 3d O 2p价带中心比GdCu2O4的价带中心向Fermi能级移近了3.4 eV,而且NdCu2O4的价带谱更窄.

XPS Study on Electronic Structure for LnCu2O4(Ln=Gd, Nd)

The core levels and valence band spectra of LnCu2O4(Ln=Gd, Nd) were recorded by XPS. It has been observed that the Ln 3d binding energies of LnCu2O4 are 0.8－0.9 eV lower than that of the corresponding rare earth oxide. On the other hand, the Cu 2p binding energies of LnCu2O4 are 0.4－0.5 eV higher than that of CuO. This has been explained by the Cu→O→Ln charge transfer in Ln－O－Cu linkage of LnCu2O4. The XPS results also show that there is no mixed valence of Cu in LnCu2O4. The X ray induced valence bands reveal that the center of Ln 4f Cu 3d O 2p valence band for Nd0.97Cu2O4 has a 3.4 eV lower binding energy compared to the center for Gd0.98Cu2O4. Besides, the width of valence band for Nd0.97Cu2O4 is narrower than that of Gd0.98Cu2O4.