Experimental energy-band dispersions and lifetimes for ruthenium

Abstract

We have determined energy-band dispersions and lifetimes for occupied and empty bands along the threefold axis of Ru using angle-resolved photoelectron spectroscopy with synchrotron radiation. The lowest valence band extends from - 7.5 eV below the Fermi energy at ${\ensuremath{\Gamma}}_{1}^{+}$ to - 5.6 eV at ${\ensuremath{\Gamma}}_{4}^{\ensuremath{-}}$ with an inverse lifetime of 1.2 eV. There is a band gap between - 5.5 and - 2.8 eV. The ${t}_{2g}$-like and ${e}_{g}$-like $\ensuremath{\Gamma}$ points are at - 2.4 eV (${\ensuremath{\Gamma}}_{6}^{\ensuremath{-}},{\ensuremath{\Gamma}}_{1}^{+}$) and at - 0.3 eV (${\ensuremath{\Gamma}}_{6}^{+}$), respectively. A ${\ensuremath{\Delta}}_{5}$, ${\ensuremath{\Delta}}_{6}$ symmetry gap extends from - 1.7 to - 0.5 eV. A comparison with band calculations is given.