Crystal Structure and Electronic Transport of Dy@C_<82>

The crystal structure of Dy@C_<82> isomer I at 298 K has been determined by Rietveld refinement for x-ray powder diffraction with synchrotron radiation. Isomer I shows a simple cubic structure (sc: Pa3^^-) with a lattice constant a of 15.78(1) Å. The C_2 axis of a C_2v-C_<82> cage aligns along the［111］direction of this crystal lattice. The C_<82> cage is orientationally disordered to satisfy a 3^^- symmetry along ［111］, which is requested in this space group. The large thermal parameter for the Dy atom estimated from the x-ray diffraction probably reflects a large disorder caused by a floating motion of the Dy atom inside the C_<82> cage as well as a ratchet-type motion of the Dy@C_<82> molecule. The electronic transport of thin film of Dy@C_<82> shows a semiconducting behavior. The energy gap E_g is estimated to be 0.2 eV. Further, the variation of valence from Dy^ <3+> to Dy^<2+> is found by metal doping into the Dy@C_<82> crystals.
identifier:10980121
identifier:https://dspace.jaist.ac.jp/dspace/handle/10119/3363