Figure 4. Normalized Peierls enthalpy variations with applied stress in Mo and W.

The Peierls enthalpy H_P is normalized by the energy barrier, E_P, calculated with DFT at zero applied stress. The applied stress, τ, is normalized by the Peierls stress, τ_P for each orientation. The symbols are the DFT data, the black lines the fits by Kocks-type power laws. We found that a single set of p and q parameters fitted all data for a given material ((p, q)=(0.94, 1.51) for Mo and (0.85, 1.27) for W).