Fermi-surface evolution in Yb-substituted CeCoIn 5

Author(s): Polyakov, A; Ignatchik, O; Bergk, B; Gotze, K; Bianchi, AD; Blackburn, S; Prevost, B; Seyfarth, G; Cote, M; Hurt, D; Capan, C; Fisk, Z; Goodrich, RG; Sheikin, I; Richter, M; Wosnitza, J | Abstract: We report results of systematic de Haas-van Alphen (dHvA) studies on Ce1-xYbxCoIn5single crystals with varying Yb concentration. For x=0.1, the well-known Fermi surfaces and the heavy effective masses of CeCoIn5(x=0) have changed only slightly. We start to observe changes of the Fermi-surface topology at x=0.2 leading to a drastic reconstruction above x=0.55. At these concentrations, the effective masses are reduced considerably to values between 0.7 and 2.6 free electron masses. For both YbCoIn5and CeCoIn5, the angular-resolved dHvA frequencies can be very well described by conventional density-functional theory calculations. Projection of the Bloch states onto atomic Yb-4f orbitals yields a 4f occupation of 13.7 electrons, in agreement with previous experimental results indicating an intermediate Yb valence of +2.3. © 2012 American Physical Society.