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Published on: December 29, 2016
Crystal structure, chemical bonding, and electrical and thermal transport in Sc5Rh6Sn18
Manuel Feig1, Lev Akselrud, Walter Schnelle
1Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Straße 23, 09596 Freiberg, Germany. roman.gumeniuk@physik.tu-freiberg.de.
Abstract:
Single crystals of Sc5Rh6Sn18 were grown from Sn-flux. The crystal structure (SG: I41/acd, a = 13.5529(2) Å, c = 27.0976(7) Å) was studied by high-resolution X-ray diffraction on powder and single crystal material as well as by TEM. All methods confirm it to crystallize with a Sc5Ir6Sn18 (space group I41/acd) type structure. The performed structural studies also suggest the presence of local domains with a broken average translational symmetry. An analysis of the chemical bonding situation reveals highly polar covalent Sc2-Sn1, Sn-Rh and Sc2-Rh bonds, two- and three-centre bonds involving Sn-atoms as well as the ionic nature of Sc1 bonding. The thermopower of Sc5Rh6Sn18 is isotropic, small and negative (i.e. dominance of electron-like charge carriers). Due to structural disorder, the thermal conductivity is lower in comparison with regular metallic systems.
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