An edge dislocation is an extra half-plane of atoms wedged into an otherwise regular crystal lattice. Every atom's displacement from its ideal lattice site follows the standard elastic edge-dislocation field, evaluated here relative to the moving dislocation core at (x₀, slip row):
δx = dx − x0
u_x(δx, δy) = (b / 2π) · [ atan2(δy, δx) + (δx·δy) / (2(1−ν)·r²) ]
with Poisson ratio ν = 0.33. Atoms compress (teal) on one side of the slip plane and stretch (orange) on the other — the elastic distortion that stores energy around the core.
- Glide — when applied stress σ ≥ yield stress τ_c, the core advances continuously along its slip plane.
- Thermal activation — below τ_c there is still a small Arrhenius-style hop probability ∝ exp(−(τ_c−σ)/kT), so raising temperature lets slip occur sub-threshold, exactly as in the 3D version.
- Permanent slip — each time the core exits the right edge it deposits one Burgers-vector step at the crystal surface (the small ledge marker) and increments the slip-event count and plastic strain γ = N·b / crystal height.