COMPLETE BAND-STRUCTURE DETERMINATION OF THE QUASI-2-DIMENSIONAL FERMI-LIQUID REFERENCE COMPOUND TITE2

The electronic structure of the layered compound 1T-TiTe2 has been stu died in detail by high-resolution angle-resolved photoelectron spectro scopy (ARPES) and density-functional band calculations. The results co nfirm the semimetallic nature of this material as due to an overlap of Te 5p- and Ti 3d-like conduction bands. We find an overall good corre spondence between experiment and theory, with ail ARPES structures acc ounted for by the: calculated band structure. Particular focus is appl ied to the bands near the Fermi level and to the Fermi-surface topolog y. Interesting behavior is observed for an essentially Ti 3d(z)2-deriv ed conduction band, whose measured Fermi vector and qualitative shape are excellently reproduced by the calculation. However, the experiment al energy dispersion of the Ti 3d,2 ARPES peak appears to be considera bly reduced with respect to band theory. From these results we obtain a picture of the electronic structure of 1T-TiTe2 as that of a Fermi l iquid with renormalized quasiparticle dispersions and a Fermi surface in accordance with Luttinger's sumrule. We show that the experimental Ti 3 d(z)2 emission is quasi-two-dimensional near the Fermi surface, w hich, together with its being remarkably unobscured, virtually free of any interference with other spectral structures or inelastic backgrou nd, makes it an ideal object for ARPES line-shape studies on a Fermi-l iquid system.