Epitaxial Bain path of antiferromagnetic tetragonal Mn

The epitaxial Bain path (EBP) of antiferromagnetic (AF) tetragonal Mn has been found by first-principles total-energy calculations using the full-potential linearized-augmented-plane-wave (FLAPW) method with two different potentials: (1) the local-spin-density-approximation without relativistic corrections (LSDA-NREL) and (2) the Perdew-Burke-Ernzerhof exchange-correlation potential in a generalized-gradient-approximation with relativistic corrections (GGA-REL). The EBP from the GGA-REL calculations shows that the tetragonal ground state of AF Mn is at (Formula presented) in close agreement with the experimental value for γ-Mn at (Formula presented) but the LSDA-NREL value 0.993 is not as close. The LSDA-NREL calculations show that when grown epitaxially on Pd(001), the AF Mn film is strained γ-Mn, but grown on V(001) the film is strained δ-Mn. The GGA-REL calculation also finds the Mn film on Pd(001) is strained γ-Mn, but on V(001) is unstable. Lattice constants for both the ground state and the metastable equilibrium state and tetragonal elastic constants for the ground state are determined with both potentials. © 2000 The American Physical Society.