题　目：Anisotropy in the electronic structure of M_n+1AX_n-phases probed by x-ray emission spectroscopy in comparison to ab initio calculations

报告人：Martin Magnuson

　　　　Thin Film Physics Division,
　　　　　　Department of Physics, Chemistry, and Biology (IFM),
　　　　　　Linköping University, Sweden

时　间：8月20日（周五）上午9:30-11:00

地　点：李薰楼468房间

欢迎参加！　 

Abstract:

An important class of nanolaminates explored at Linköping University is the Mn+1AXn-phases, which are carbides and nitrides that form layered ternary ceramics. For example, the anisotropy in the electronic structure of an epitaxially grown film of Ti₃SiC₂ was investigated and compared to amorphous silicon. The anisotropy of the electronic structure and chemical bonding of Ti₃SiC₂ has been investigated using bulk-sensitive and element selective x-ray fluorescence spectroscopy. The differences between the in-plane and out-of-plane bonding at the internal interfaces of the nanolaminates were investigated in detail by angle-resolved precision measurements. The Ti L, C K and Si L₁, L_2,3 emission spectra of Ti₃SiC₂ are compared with first-principles density-functional theory including core-to-valence dipole transition matrix elements. Strongly hybridized spectral shapes are detected for Si imbedded in Ti₃SiC₂. The anisotropy of the electronic structure and chemical bonding is discussed in relation to the various hybridization regions of related M_n+1AX_n-phases and macroscopic properties such as conductivity, elasticity and thermopower.