Abstract
The electronic structure in the new transition-metal carbide has been investigated by bulk-sensitive soft x-ray emission spectroscopy and compared to the well-studied and TiC systems. The measured high-resolution Ti , C , and Si x-ray emission spectra are discussed with ab initio calculations based on density-functional theory including core-to-valence dipole matrix elements. The detailed investigations of the Ti-C and Ti-Si chemical bonds provide increased understanding of the physical properties of these nanolaminates. A strongly modified spectral shape is detected for the intercalated Si monolayers due to Si hybridization with the Ti orbitals. As a result of relaxation of the crystal structure and the charge-transfer from Ti (and Si) to C, the strength of the Ti-C covalent bond is increased. The differences between the electronic and crystal structures of and are discussed in relation to the number of Si layers per Ti layer in the two systems and the corresponding change of materials properties.
- Received 11 August 2006
DOI:https://doi.org/10.1103/PhysRevB.74.205102
©2006 American Physical Society