LnCu_2O_4(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 LnCu_2O_4(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.