Hybridization of 4f states in heavy-fermion compounds YbRh2Si2 and YbIr2Si2

The heavy-fermion compounds YbRh2Si2 and YbIr2Si2 were studied by means of angle-resolved photoemission. The observed dispersion and splittings of the 4f(13) bulk and surface emissions are explained in terms of a simplified periodic Anderson model by a k dependence of the electron hopping matrix element between the 4f and valence-band states. (c) 2006 Elsevier B.V. All rights reserved.