Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Spin Structures and Magnetic Phase Transitions

MA 18.4: Vortrag

Mittwoch, 25. März 2009, 11:00–11:15, HSZ 401

Electronic structure and nesting-driven enhancement of the RKKY interaction at the magnetic ordering propagation vector in Gd₂PdSi₃ and Tb₂PdSi₃ — •Dmytro Inosov¹, Daniil Evtushinsky², Andreas Koitzsch², Volodymyr Zabolotnyy², Sergey Borisenko², Alexander Kordyuk², Matthias Frontzek³, Michael Loewenhaupt³, Wolfgang Löser², Irina Mazilu², Holger Bitterlich², Günter Behr², Jens-Uwe Hoffmann⁴, Rolf Follath⁵, and Bernd Büchner² — ¹MPI-FKF, Stuttgart, Germany — ²IFW-Dresden, Germany — ³TU-Dresden, Germany — ⁴HMI, Berlin, Germany — ⁵BESSY GmbH, Berlin, Germany.

We present first-time measurements of the Fermi surface and low-energy electronic structure of intermetallic compounds Gd₂PdSi₃ and Tb₂PdSi₃ by means of angle-resolved photoelectron spectroscopy (ARPES). We show that the Fermi surface in both compounds consists of an electron barrel at the Γ point surrounded by spindle-shaped electron pockets originating from the same band, with the band bottom of both features lying at 0.5 eV below the Fermi level. From the experimentally measured band structure, we estimate the momentum-dependent RKKY coupling strength and demonstrate that it is peaked at the 1/1pt2ΓK wave vector. Comparison with neutron diffraction data from the same crystals shows perfect agreement of this vector with the propagation vector of the low-temperature in-plane magnetic order, thereby demonstrating the decisive role of the Fermi surface geometry in explaining the complex magnetically ordered ground state of ternary rare earth silicides.