  High-entropy alloys (HEAs) with concentrated solid solutions are conceived to
possess a rugged atomic and energy landscape in which dislocation motion
necessarily proceeds to accommodate mechanical deformation. Fundamental
questions remain as to how rough the energy landscape is and to what extent it
can be influenced by the local ordering of their constituent elements. Here, we
construct and report the potential energy landscape (PEL) governing screw
dislocation motion in refractory HEAs that reveals a hierarchical and
multilevel structure with a collection of small basins nested in large
metabasin. This striking feature pertaining to HEAs exerts a trapping force and
back stress on saddle point activations, retarding dislocation movement. By
introducing chemical short-range order, the energy landscape is smoothed but
skewed to different degrees that shifts the rate-liming process from kink-glide
to kink-pair nucleation. The chemical disorder-roughened PEL in HEAs, analogous
to structural disorder induced in metallic glasses, signifies the role of
various barrier-hopping processes underlying the extraordinary mechanical
behaviors of the two distinct groups of materials.
