Electronic structure and chemical bonding in Ti2AlC investigated by soft x-ray emission spectroscopy

• Theelectronic structure of the nanolaminated transition metal carbide Ti2AlC hasbeen investigated by bulk-sensitive soft x-ray emission spectroscopy. The measuredTi L, C K, and Al L emission spectra arecompared with calculated spectra using ab initio density-functional theory includingdipole matrix elements. The detailed investigation of the electronic structureand chemical bonding provides increased understanding of the physical propertiesof this type of nanolaminates. Three different types of bondregions are identified: The relatively weak Ti 3d–Al 3p bond1  eV below the Fermi level and the Ti 3d–C 2pand Ti 3d–C 2s bonds which are stronger and deeperin energy are observed around 2.5 and 10  eV below theFermi level, respectively. A strongly modified spectral shape of the3s final states in comparison to pure Al is detectedfor the intercalated Al monolayers indirectly reflecting the Ti 3d–Al3p hybridization. The differences between the electronic and crystal structuresof Ti2AlC, Ti3AlC2, and TiC are discussed in relation tothe number of Al layers per Ti layer in thetwo former systems and the corresponding change of the unusualmaterials properties.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Keyword

band structure

bonds (chemical)

titanium compounds

aluminium compounds

X-ray emission spectra

ab initio calculations

density functional theory

Fermi level

crystal structure

NATURAL SCIENCES

NATURVETENSKAP

Physics

Publication and Content Type

ref (subject category)

art (subject category)