Angle-resolved photoemission studies of TiC(111) and TiC(100)

Abstract

Oriented single-crystal faces of TiC (100)-(1×1) and TiC (111)-Ti (1×1) have been studied with angle-resolved photoelectron spectroscopy using synchrotron radiation for 8≤hν≤70 eV. From normal-emission spectra, criticalpoint energies have been determined for the occupied carbon 2s band (10-13 eV below EF) and for the occupied Ti 3d-C 2p band (L3′=-6 eV, L3′=-3 eV, X4′-Δ1=-4 eV, X5′=-0.5 eV, and Δ5=-0.8 eV). Recent band calculations are shown to be qualitatively correct, although most calculations place the bands too close to the Fermi energy EF. Critical points in the empty Ti 4s-derived band (L1′=8.7 eV and X1=11.5 eV above EF) have been identified through studies of final-state effects in normal emission. Three-dimensional density-of-states features were observed in normal-emission spectra, although such spectra should sample only the high-symmetry lines Γ-Δ-L and Γ-Λ-L; these could be due to the effects of bulk vacancies in the TiC0.93 crystal or to surface inhomogeneities incurred in the preparation process (ion etching and annealing). © 1980 The American Physical Society.