Fermi surfaces of rare-earth nickel borocarbides

A full three-dimensional study of the Fermi surface of LuNi2B2C is presented, using positron annihilation. The previously identified nesting feature, part of a complex multiply connected Fermi surface sheet, is clearly revealed and observed to extend across approximately 20% of the Brillouin zone. A cuboidal Fermi surface sheet is also found, in agreement with de Haas-van Alphen observations. The Fermi surface topology of the rare-earth nickel borocarbides is shown to vary little for rare-earth elements such as Er, Tm and Yb, suggesting that this topology is broadly common.