Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 30: Electron Theory of Magnetism

MA 30.1: Talk

Thursday, March 25, 2010, 17:00–17:15, H22

Electronic structure, localization and spin-state transition in Cu-substituted FeSe — •Stanislav Chadov¹, Daniel Schärf¹, Gerhard H. Fecher¹, Claudia Felser¹, Lijun Zhang², and David J. Singh² — ¹Institut für Anorganische und Analytische Chemie, Johannes Gutenberg Universität, 55099 Mainz — ²Material Science and Technology Division, Oak Ridge National Laboratory, TN 37831-6114, USA

We report the density functional studies of the Fe_1−xCu_xSe alloy using the coherent potential approximation (CPA) method. Magnetic behaviour was investigated using the disordered local moment (DLM) approach. We find that Cu occurs in a nominal d¹⁰ configuration and is highly disruptive to the electronic structure of the Fe sheets. This would be consistent with a metal-insulator transition due to Anderson localization. We further find a strong crossover from a weak moment itinerant system to a local moment magnet at x ≈ 0.12. We associate this with the experimentally observed jump near this concentration. Our results are consistent with the characterization of this concentration-dependent jump as a transition to a spin-glass.

The financial support by the SFB/TRR49 is gratefully acknowledged.