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CaB_6: a new semiconducting material for spin electronics

H. J. Tromp·P. van Gelderen·P. J. Kelly·G. Brocks·P. A. Bobbert
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Abstract

Ferromagnetism was recently observed at unexpectedly high temperatures in La-doped CaB_6. The starting point of all theoretical proposals to explain this observation is a semimetallic electronic structure calculated for CaB_6 within the local density approximation. Here we report the results of parameter-free quasiparticle calculations of the single-particle excitation spectrum which show that CaB_6 is not a semimetal but a semiconductor with a band gap of 0.8 eV. Magnetism in La_xCa_{1-x}B_6 occurs just on the metallic side of a Mott transition in the La-induced impurity band.

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H. J. Tromp, P. van Gelderen, P. J. Kelly, G. Brocks, P. A. Bobbert. 2000-11-07. CaB_6: a new semiconducting material for spin electronics. https://doi.org/10.1103/physrevlett.87.016401

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