Structural, electronic and mechanical properties of Mo2GeC under strain engineering

Abstract

A new type of nitride and carbide with excellent properties of metals and ceramics, known as MAX phase materials, is a new guide for structural modification in various engineering applications and novel technologies. The Mo 2 GeC MAX phase is regarded as a promising material for applications such as new coatings, high pressure resistant materials, and fission and fusion program reactors. In this work, the structural, electronic, and mechanical properties of Mo 2 GeC under strain engineering are predicted by first-principles calculations. When Mo 2 GeC is tensioned or compressed by various strain conditions, effective mass decreases and increases in electrical conductivity are observed. Under uniform biaxial strain, the degeneracy at the top of the valence band is significantly increased. Mo 2 GeC possesses small Young’s modulus, shear modulus, and large bulk modulus, indicating that it can be desired for large strain engineering applications. However, the layered structure of Mo 2 GeC leads to low shear strength and hardness, which makes it less resistant to shear deformation. We also investigate the structural deformation and mechanical properties of Mo 2 GeC in different directions of uniaxial tensile strain up to the fracture limit. For tension along the a -direction, the strain ε value is 45% when Mo 2 GeC reaches the ideal tensile strength. The different bond strengths of Mo 2 GeC explain its anisotropy and show more significant differences under different strain conditions. Our results provide a strategy for tuning the various properties of Mo 2 GeC. Mo 2 GeC is subjected to uniaxial strain in different directions