Decoupling atomic diffusion degeneracy in L12 intermetallics

In this work, a degenerate diffusion state is identified for common L1(2) intermetallics in well-defined five-frequency model (FFM) and anti-site bridge model (ASB). The relative energy barrier E-4/E-B(beta ->alpha) (E-4 in FFM and E-B(beta ->alpha) in ASB) of the degenerate state serves as a decomposer which not only bifurcates the degenerate pathways, but also determines the most probable diffusion model. The diffusion coefficients obtained from the most probable diffusion model coincides the experimental value. We find the proposed decomposer complies with the Onsager phenomenological theory and atomistic correlation understanding, and is also supported by the relative work W-FFM/W-ASB done by electronic wind force.