Two Ternary Europium Chalcogenides EU1-xGa2Te4 (x≈0.19) and EuY2Se4,Experimental and Theoretical Investigations

摘要

Two ternary europium chalcogenides,Eu1-xGa2Te4 (x ≈ 0.19) (1) and EuY2Se4 (2),have been synthesized by a facile solid-state route using boron as the reducing reagent.Eu1-xGa2Te4crystallizes in the tetragonal space group Ⅰ4/mcm with a =8.2880(9),c =6.7439(12) (A),V =463.24(13) (A)3,and Z =2.EuY2Se4 crystallizes in the orthorhombic space group Pnma with a =12.4726(16),b =4.1204(6),c =14.849(2) (A),V=763.11(19) (A)3,and Z=4.Eu1-xGa2Te4 belongs to the TlSe-type 3D closed structure,while EuY2Se4 adopts the CaFe2O4-type 3D channel structure.The optical band gap of Eu1-xGa2Te4 is determined to be 0.48 eV.Electronic structures of 1 and 2 are calculated using TB-LMTO software.