Local structures of III-V diluted magnetic semiconductors Ga 1 − x Mn x As studied using extended x-ray-absorption fine structure

Local structures around Mn in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ ($x=0.005$ and 0.074) films have been studied using Mn $K$-edge extended x-ray-absorption fine structure. In the ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ films, Mn atoms are substituted into the Ga sites in the zinc-blende-type GaAs lattice. The Mn-As bond length (2.49\char21{}2.50 \AA{}) in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ is 2\char21{}3 % larger than the Ga-As bond length (2.44 \AA{}) in bulk GaAs. The longer Mn-As bonds cause local disorder in the GaAs lattice, the degree of which increases with the Mn composition.