An investigation was made of the structure and the equation of state of compound MgB2 at high pressure using the full-potential linearized muffin-tin orbital scheme within the generalized gradient approximation correction in the frame of density functional theory. Through the quasi-harmonic Debye model, in which the phononic effects were considered, the bulk modulus and the thermal expansion of MgB2 were successfully obtained.

First-Principles Calculations for Structure and Equation of State of MgB2 at High Pressure. X.R.Chen, H.Y.Wang, Y.Cheng, Y.J.Hao: Physica B, 2005, 370[1-4], 281-6

Figure 13

Elastic Constants as a Function of Pressure

(Vertical axis gives change in parameter, normalized with respect to ambient value)