First-Principles Calculations of Elastic Constants of Superconducting MgB₂

The five independent elastic constants of superconducting MgB₂ are obtained using the first-principles plane wave method with the new relativistic analytic pseudopotential of the Hartwigsen--Goedecker--Hutter (HGH) scheme in the frame of local density approximation. The dependences of bulk modulus on temperature and pressure are also obtained. It is suggested that the HGH-type pseudopotentials are successful in investigating the ground-state mechanical properties of any solids.