Mechanical Properties and Stability of Body-Centered-Tetragonal C8 at High Pressures

Abstract

Abstract The structural, mechanical, electronic properties and stability of body-centered-tetragonal C8 (Bct-C8) were determined by using the first-principles calculations. Bct-C8 is identified to be mechanically and dynamically stable at a pressure range from 0 to 100 GPa. The elastic anisotropy, average acoustic velocity and Debye temperature of Bct-C8 at ambient and high pressures were studied. The ideal stresses at large strains of Bct-C8 were examined; the results showed that it would cleave under the tensile strength of 72 GPa or under the shear strength of 70 GPa, indicating that Bct-C8 is a potential superhard material.