Synthesis of Cr2AuC via thermal substitution reaction in Au-covered Cr2GaC and Cr2GeC thin films

• DOI: 10.1016/j.rinma.2023.100403
• Publication Date: 2023-05-19T07:23:57Z
• Authors: Yuchen Shi; Shun Kashiwaya; Pernilla Helmer; Jun Lu; Mike Andersson; Andrejs Petruhins; Johanna Rosen; Lars Hultman
• Keywords: Lattice (music); Substitution (logic)

Intercalation of noble metals into non-van der Waals solids provides a new avenue to synthesize novel nanolaminated compounds with distinct material properties. Herein, we use solid-state reaction at 400 °C prepare Cr2AuC from two Cr-based Mn+1AXn phase precursors and demonstrate the formation upon full replacement Ga layers Au in Cr2GaC thin films via thermal substitution reaction. The resulting exhibits 2.7% lattice expansion relative original Cr2GaC, whereas Ge Cr2GeC film was sparsely replaced by Au, as revealed electron microscopy x-ray diffraction analysis. To explain observed differences, using ab initio calculations, consider bonding properties Cr2GeC, energetic driving forces for evaluating mixing free energy on both A-sites MAX phases, A-elements surrounding lattice. results suggest that it is somewhat easier mix A-site than substantially Au-lattice Ge. Finally, discuss how gained insights can be consulted exploring wider class phases intercalated metals.