Atomic image around Mn atoms in diluted magnetic semiconductor Cd 0.6Mn 0.4Te obtained from X-ray fluorescence holography

Abstract

The lattice constant of diluted magnetic semiconductors Cd 1− x Mn x Te obtained from X-ray diffraction linearly changes with the Mn concentration, while extended X-ray absorption fine structure (EXAFS) studies showed that the bond lengths are almost kept as their own values. In order to investigate how the MnTe 4 tetrahedra can be stretched in the large Cd–Te lattice, we have measured Mn Kα X-ray fluorescence holography on Cd 0.6Mn 0.4Te single crystal and obtained the wider atomic images around the Mn atoms than EXAFS. The atomic image intensities of the first-, third- and fifth-neighbor anion Te became weak, and the fourth- and sixth-neighbor cation Cd or Mn intensities almost unchanged. The second-neighbor Cd or Mn atomic images look highly shifted from the appropriate positions. Thus, it is concluded that the lattice of this mixed crystal is highly distorted in the intermediate range, and the distortion in the anion sublattice is induced to the larger distance from the central Mn atom than that in the cation sublattice.