Strain effect on structural stability and mechanical and thermal properties of rare earth molybdates

Abstract Rare earth molybdates have emerged as promising candidates for thermal barrier coatings owing to their high melting points, excellent chemical and thermal stability, and good ductility. In this work, we employ density functional theory to systematically investigate the influence of strain on the crystal structure, mechanical properties, and thermal conductivity of Dy 2 MoO 6 and Lu 2 MoO 6 . Our results indicate that both molybdates retain good structural stability under strains ranging from –6% (compressive) to +10% (tensile). A moderate compressive strain is found to enhance the elastic constants and moduli of both compounds. Moreover, applied strain leads to a reduction in the minimum thermal conductivity. Specifically, under a tensile strain of 10%, the minimum thermal conductivity of Dy 2 MoO 6 (Lu 2 MoO 6 ) decreases by approximately 23% (40%) relative to the unstrained case. The thermal conductivity exhibits a monotonic decline with increasing both compressive and tensile strain. Further analysis reveals that strain‐mediated reduction in thermal conductivity is achieved predominantly through weakened interatomic bonding rather than enhanced lattice anharmonicity. This study offers valuable insights for the strain‐engineered design of materials with low thermal conductivity.