<span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>CaB</mi></mrow><mrow><mn>6</mn></mrow></msub></mrow></math></span>: A New Semiconducting Material for Spin Electronics

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

doi:10.1103/PhysRevLett.87.016401

${CaB}_{6}$ : A New Semiconducting Material for Spin Electronics

H. J. Tromp, P. van Gelderen, P. J. Kelly, G. Brocks, and P. A. Bobbert

Phys. Rev. Lett. 87, 016401 – Published 18 June 2001

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 $0.8 \pm 0.1 eV$ . Magnetism in ${La}_{x} {Ca}_{1 - x} B_{6}$ occurs just on the metallic side of a Mott transition in the La-induced impurity band.

Received 19 October 2000

DOI:https://doi.org/10.1103/PhysRevLett.87.016401

Authors & Affiliations

H. J. Tromp¹, P. van Gelderen^1,2, P. J. Kelly¹, G. Brocks¹, and P. A. Bobbert³

¹Faculty of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
²Faculty of Sciences and Research Institute for Materials, University of Nijmegen, P.O. Box 9010, 6525 ED Nijmegen, The Netherlands
³Department of Applied Physics and COBRA Research School, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands