Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.85: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Fermi Surface of the Half Heusler Compounds Ce_1−xLa_xBiPt — •A. D. Bianchi¹, J. Wosnitza¹, N. Kozlova², D. Eckert², L. Schultz², I. Opahle², S. Elgazzar², M. Richter², J. Hagel³, M. Doerr³, G. Goll⁴, H. v. Löhneysen^4,5, G. Zwicknagl⁶, T. Yoshino⁷, and T. Takabatake⁷ — ¹HLD, Forschungszentrum Rossendorf, Postfach 51 01 19, D-01314 Dresden — ²IFW Dresden, D-01171 Dresden — ³Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden — ⁴Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe — ⁵Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe — ⁶Institut für Mathematische Physik, Technische Universität Braunschweig, D-38106 Braunschweig — ⁷Department of Quantum Matter, ADSM, Hiroshima University, Higashi-Hiroshima 739-8530, Japan

We report on the Fermi surface in the correlated half-Heusler compound Ce_1−xLa_xBiPt. In CeBiPt we find a field-induced change of the electronic band structure as discovered by electrical-transport measurements in pulsed magnetic fields. For magnetic fields above ∼25 T, the charge-carrier concentration determined from Hall-effect measurements increases nearly 30%, whereas the Shubnikov–de Haas (SdH) signal disappears at the same field. In the non-4f compound LaBiPt the Fermi surface remains unaffected, suggesting that these features are intimately related to the Ce 4f electrons. Electronic band-structure calculations point to a 4f-polarization-induced change of the Fermi-surface topology. In order to test this hypothesis, we have measured the (SdH) signal in a Ce_0.95La_0.05BiPt sample with a low La concentration.