ABSTRACT
Accurate low temperature charge transport measurements in combination with high-precision x-ray diffraction experiments have allowed detection of the symmetry lowering in the single domain Tm0.19Yb0.81B12 crystals that belong to the family of dodecaborides with metal-insulator transition. Based on the fine structure analysis we discover the formation of dynamic charge stripes within the semiconducting matrix of Tm0.19Yb0.81B12. The charge dynamics in these conducting nano-size channels is characterized by broad-band optical spectroscopy that allowed estimating the frequency (~2.4 × 1011 Hz) of quantum motion of the charge carriers. It is suggested that cooperative Jahn-Teller effect in the boron sublattice is a cause of the large-amplitude rattling modes of the Tm and Yb ions responsible for the 'modulation' of the conduction band along one of the [Formula: see text] directions through the variation of 5d-2p hybridization of electron states.
ABSTRACT
Procedure for crystal structure refinement using precession electron diffraction data and Bloch-wave method for accounting multibeam scattering is described. Refinement procedure takes into account features of precession geometry. Refining model consists of structural and reduced parameters determining dynamic diffraction. Difference between measured and calculated dynamic intensities of reflections is minimized with application of a nonlinear least squares method. As test example we used Si single nanocrystals. The influence of the reduced parameters on the quality of the obtained model is discussed. Refinement procedure is a part of ASTRA software.
