Surface Effects in Eu Intermetallics - a Resonant Photoemission-Study
Surface Effects in Eu Intermetallics - a Resonant Photoemission-Study
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Eu 金属间化合物的表面效应 - 共振光电发射研究
DOI：
10.1103/physrevb.28.2017
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发表时间：
1983
影响因子：
3.7
通讯作者：
A. Puschmann
中科院分区：
文献类型：
--
作者：
W. Schneider;C. Laubschat;G. Kalkowski;J. Haase;A. Puschmann
采用共振4d\ensuremath{\right row}4f$光发射技术研究了Eu\char22{}过渡金属化合物Eu${\mathrm{Ag}}_{5}$、Eu${\mathrm{Rh}}_{2}$、Eu${\mathrm{Pt}}_{5}$和Eu${\mathrm{Pd}}_{5}$。在二价Eu${\mathrm{Ag}}_{5}$中，发现终态$4{f}^{6}$多分量的表面核能级位移为0.75 eV。对于三价铕化合物Eu${\ mathm {Pt}}_{5}$和Eu${\ mathm {Pd}}_{5}$以及混合价铕化合物Eu${\ mathm {Rh}}_{2}$，观察到表面价态向低价态转变。对于Eu${\ mathm {Pt}}_{5}$，注意到一个非均匀混合价表面，表明表面价跃迁具有很强的配位依赖性。根据$4f$光发射和光吸收阈值能量，讨论了末态$4f$屏蔽轨道的能量位置。
The Eu\char22{}transition-metal compounds Eu${\mathrm{Ag}}_{5}$, Eu${\mathrm{Rh}}_{2}$, Eu${\mathrm{Pt}}_{5}$, and Eu${\mathrm{Pd}}_{5}$ were studied by resonant $4d\ensuremath{\rightarrow}4f$ photoemission techniques. In divalent Eu${\mathrm{Ag}}_{5}$, a surface core-level shift of the final-state $4{f}^{6}$ multiplet components of 0.75 eV is found. For the trivalent Eu compounds Eu${\mathrm{Pt}}_{5}$ and Eu${\mathrm{Pd}}_{5}$ as well as for the mixed-valence compound Eu${\mathrm{Rh}}_{2}$, a surface valence change to the lower-valence state is observed. For Eu${\mathrm{Pt}}_{5}$, an inhomogeneously mixed-valence surface is noticed, pointing to a strong coordination dependence of the surface valence transition. The energy position of the final-state $4f$ screening orbital is discussed on the basis of $4d$ photoemission and photoabsorption threshold energies.