Recent experiments suggest that bcc Mg can be stabilized when grown together with bcc Nb in Mg/Nb multilayer films at ambient conditions. This finding is remarkable as (pure) bcc Mg has only been observed under very high pressures and is in fact (mechanically) unstable under room conditions. Density functional theory calculations were performed to gain insight into the stability of Mg in the bcc structure. Calculations of the thermodynamic

electronic and structural stability of bcc Mg show that this structure is in fact metastable under thin film conditions

when Mg grows epitaxially on bcc Nb

in agreement with experiments.