Thermally activated glide of dislocation is a key point for understanding the plastic deformation of metals. The screw dislocation in bcc metals is an archetypical case for which a large quantity of experimental data has been published in the scientific literature. It is then possible to compare these data to the theoretical predictions realized from the Vineyard statistical theory [1,2]. Such a theory is an essential tool allowing to perform a scale transition from atomistic computations [3] toward macroscopic scale at which are realized the deformation tests.
The aim of our research will be to test Vineyard theory in comparison with molecular dynamics simulations [4]. Some preliminary computations have shown a significant discrepancy that is not present when we repeat the comparison for point-like defect as vacancies or self-interstitial atoms. The discrepancy of the theory will have to be reduce within a new theoretical development. Our new theory should allow some predictions in agreement with macroscopic tensile test in bcc metals [5].

[1] Vineyard G.H., J. Phys. Chem. Solids 3, 121 (1957).
[2] Proville L., Rodney D., Marinica M-C., Nature Mater. 11, 845 (2012).
[3] Proville L., Ventelon L., Rodney D., Phys. Rev. B 87, 144106 (2013).
[4] Proville L., Choudhury A., Nature Mater. 23, 47 (2024).
[5] Caillard D., Acta Mater. 58, 3504 (2010).