Ab initio thermodynamics and phase diagram of solid magnesium:: A comparison of the LDA and GGA

The finite temperature density functional theory and quasiharmonic lattice dynamics have been used to compute numerous thermodynamic properties of hexagonal close packed magnesium using both the local density approximation (LDA) and the generalized gradient approximation (GGA) for the exchange-correlation potential. Generally, it is found that there exist only minor differences between the LDA and GGA computed properties, with both giving good agreement with experiment. The hcp-bcc phase boundary has also been computed and is found to be in agreement with experimental observation. Again, only slight differences are found between the LDA and GGA. (c) 2006 American Institute of Physics.