6533b86dfe1ef96bd12ca8c3

RESEARCH PRODUCT

Doped semiconductors as half-metallic materials: Experiments and first-principles calculations ofCoTi1−xMxSb(M=Sc, V, Cr, Mn, Fe)

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This work reports experiments and first-principles calculations on the substitutional semiconducting $C{1}_{b}$ compound $\mathrm{Co}{\mathrm{Ti}}_{1\ensuremath{-}x}{M}_{x}\mathrm{Sb}$. Diluted magnetic semiconductors have been prepared by substituting titanium in the semiconducting compound CoTiSb by other $3d$ transition elements $M$. Self-consistent calculations of the electronic structure predict some of the materials to be half-metallic ferromagnets. The structural, electronic, electric, and magnetic properties of the pure and substituted materials have been investigated. It is found from the experiments that substitution of up to 10% Ti by Fe, Mn, Cr, and V does not affect the crystalline structure and the lattice mismatch is less than 0.5% in the substituted compounds. The electric properties can be tuned from semiconducting to metallic by using different dopants. The $M=\mathrm{Cr}$-doped compound exhibits a metal to semiconductor transition. Photoemission spectroscopy and conductivity measurements agree well with the calculated electronic structure. The measured Curie temperature of the Fe-substituted alloy is far above room temperature $(g700\phantom{\rule{0.3em}{0ex}}\mathrm{K})$. This fact and the very low lattice mismatch between the substituted and the pure compound make this material a serious candidate for future electronic applications, in particular for magnetoelectronics and spintronics.