The electronic structures of two new quaternary polar intermetallic compounds of MxCa9-xIn8Ge8 (M = Eu, Sr; x = 3.13(2), 3.23(3)) have been investigated using tight-binding, linear muffin-tin orbital (TB-LMTO) method to understand the observed novel orthorhombic structure type and interatomic interactions among anionic components forming the 3-dimensional (3D) framework. Orbital contributions from two types of cations are also observed in the valence band region, which indicates a certain degree of interatomic interactions exist between cations and anions resulting in a pseudogap at the Fermi level (EF). A crystal orbital Hamilton population (COHP) analysis for five distinct anionic interactions within the 3D framework proves that the averaged In-Ge COHP curve for the InGe4 tetrahedron is nearly optimized at EF, whereas the Ge-Ge COHP curve for Ge2 dimer contains a small anti-bonding character. The unfavorable anti-bonding characters are compensated by large numbers of bonding interactions between cations and anions. Electron localization function (ELF) displays that attractors observed between In2-Ge2 and In2-Ge4 bond on the �12-membered ring� are relatively weaker than others observed in the rest of the pentagonal geometries due to the elongated bond distances. The attractors between In and Ge are mostly polarized toward Ge atoms due to the electronegativity difference. The obtained effective magnetic moment of Eu3.13(2)Ca5.87In8Ge8 is 7.12 �B/Eu atom, and ?P= -2.58K indicating a relatively low temperature antiferromagnetic (AFM) ordering of Eu atom.

Theoretical investigation and magnetism study for two novel polar intermetallic compounds: MxCa9-xIn8Ge8 (M = Eu, Sr; x = 3.13(2), 3.23(3))

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.