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Electronic pseudogap-driven formation of new double-perovskite-like borides within the Sc2Ir6-xTxB (T = Pd, Ni; x = 0-6) series.
- Source :
-
Inorganic chemistry [Inorg Chem] 2015 Apr 20; Vol. 54 (8), pp. 4056-63. Date of Electronic Publication: 2015 Apr 07. - Publication Year :
- 2015
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Abstract
- Analysis of the electronic density of states of the hypothetical ternary double-perovskite-like phases "Sc2T6B (T = Ir, Pd, Ni)" reveals the presence of deep and large pseudogaps between 61 and 68 valence electrons (VE) as well as a strong peak at 69 VEs. Subsequently, crystal orbital Hamilton population (COHP) bonding analysis shows that the heteroatomic T-B and Sc-T interactions are optimized in Sc2Ir6B (63 VE) but not in "Sc2Pd6B (69 VE)" and "Sc2Ni6B (69 VE)", thus indicating less stability for these VE-richer phases. These findings point out the possibility of discovering new double-perovskite-like borides through chemical substitution and lead to the study of the Sc2Ir6-xPdxB and Sc2Ir6-xNixB (x = 0-6; VE = 63-69) series, for which powder samples and single crystals were synthesized by arc melting the elements. Superstructure reflections were observed in the powder diffractograms of Sc2Ir6-xPdxB and Sc2Ir6-xNixB for x = 0-5 and VE = 63-68, thereby showing that these phases crystallize in the double-perovskite-like Ti2Rh6B-type structure (space group Fm3̅m, Z = 4). Single-crystal and Rietveld refinement results confirm and extend these findings because Pd (or Ni) is found to mix exclusively with Ir in all quaternary compositions. For x = 6, no superstructure reflections were observed, in accordance with the theoretical expectation for the 69 VE phases.
Details
- Language :
- English
- ISSN :
- 1520-510X
- Volume :
- 54
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Inorganic chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 25848819
- Full Text :
- https://doi.org/10.1021/acs.inorgchem.5b00292