Atomic-Scale Tuning of Tsai-Type Clusters in RE-Au-Si Systems (RE = Gd, Tb, Ho).

ABSTRACT: Tsai-type quasicrystals and approximants are distinguished by a cluster unit made up of four concentric polyhedral shells that surround a tetrahedron at the center. Here we show that for Tsai-type 1/1 approximants in the RE-Au-Si systems (RE = Gd, Tb, Ho) the central tetrahedron of the Tsai clusters can be systematically replaced by a single RE atom. The modified cluster is herein termed a "pseudo-Tsai cluster" and represents, in contrast to the conventional Tsai cluster, a structural motif without internal symmetry breaking. For each system, single-phase samples of both pseudo-Tsai and Tsai-type 1/1 approximants were independently prepared as millimeter-sized, faceted, single crystals using the self-flux synthesis method. The full replacement of tetrahedral moieties by RE atoms in the pse

SUBMITTER: Gebresenbut G 

PROVIDER: S-EPMC7467681 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature