Ruotsalainen Kari O, Sahle Christoph J, Ritschel Tobias, Geck Jochen, Hosoda Masayuki, Bell Christopher, Hikita Yasuyuki, Hwang Harold Y, Fister Tim T, Gordon Robert A, Hämäläinen Keijo, Hakala Mikko, Huotari Simo
Department of Physics, University of Helsinki, PO Box 64, FI-00014, Finland.
J Phys Condens Matter. 2015 Aug 26;27(33):335501. doi: 10.1088/0953-8984/27/33/335501. Epub 2015 Jul 29.
We present an investigation of the valence-electron excitation spectra including the collective plasmon modes of SrTiO3, LaAlO3 and their heterostructures with non-resonant inelastic x-ray scattering. We analyse the spectra using calculations based on first principles and atomic multiplet models. We demonstrate the feasibility of performing valence IXS experiments in a total reflection geometry. Surprisingly, we find that the plasmon, interband and semicore excitations in multilayers are well described as a superposition of bulk-compound spectra even in a superstructure composing of layers of only one atomic layer thickness.
我们利用非共振非弹性X射线散射对包括SrTiO₃、LaAlO₃及其异质结构的价电子激发光谱进行了研究，其中包括集体等离子体激元模式。我们使用基于第一性原理和原子多重态模型的计算来分析光谱。我们证明了在全反射几何结构中进行价电子非弹性X射线散射实验的可行性。令人惊讶的是，我们发现即使在仅由一个原子层厚度的层组成的超结构中，多层中的等离子体激元、带间和半芯激发也能很好地描述为体化合物光谱的叠加。
