LAUSR

Abstract In this work, the first-principles calculation was employed to perform the investigations of the structural properties, elastic constants and moduli, anisotropy in elastic properties and thermal conductivities of (α, β, γ)-LiAlSi2O6. The obtained cohesive energies and formation enthalpies show that all LiAlSi2O6 are energetically stable and α-C2/c LiAlSi2O6 is the most stable phase. The elastic properties, including bulk, shear and Young's moduli (B, G and E), Poisson's ratio v and hardness HV were computed based on the single-crystal elastic constants. α-C2/c LiAlSi2O6 has the largest G, E and HV values. The elastic anisotropy was characterized by the elastic anisotropic indexes, surface constructions and projections of elastic modulus. It can be found that all LiAlSi2O6 show anisotropic elasticity and the order is α-P21/c > γ > β > α-C2/c. The thermal conductivities and their anisotropy of LiAlSi2O6 were also discussed by Long's and Cahill's models, and the results indicate that all LiAlSi2O6 exhibit potential for insulation materials.