Experimental energy bands, exchange splittings, and lifetimes for Ni in the vicinity of the x-point

Abstract

Angle-resolved photoelectron spectroscopy using synchrotron radiation has been used to determine energy band dispersions along the ΓKX and ΓX directions in nickel. A detailed picture of spin-dependent energy levels and band topology around the symmetry point X has been derived. We have measured the exchange splitting for different band symmetries and find the splitting for the X 2-S 4 band along (110) to be 0.17 eV. For the X 5-S 3 band we find a splitting of 0.33 eV which is in close agreement with the value found earlier for the Σ 2 band. This can be explained by different self-energy corrections for t 2g and e g-type states respectively. Our values for the energy positions (inverse lifetimes) are the following: X 2↓ = −0.04 eV (0.08 eV, X 2↑ = −0.24 eV (0.19 eV), X 5↑ = −0.11 eV.