<p>Light-induced phase transitions offer a method to dynamically modulate topological states in bulk complex materials. Yet, next-generation devices demand nanoscale architectures with contact resistances near the quantum limit and precise control over local electronic properties. The layered material WTe₂ has gained attention as a probable Weyl semimetal, with topologically protected linear electronic band crossings hosting massless chiral fermions. Here we demonstrate a local phase transition facilitated by the light-induced shear motion of a single atomic layer at the surface of bulk WTe₂, thereby opening the door to nanoscale device concepts. Ultrafast terahertz fields enhanced at the apex of an atomically sharp tip couple to the key interlayer shear mode of WTe₂ via a ferroelectric dipole at the interface, inducing a structural phase transition at the surface to a metastable state. Subatomically resolved differential imaging, combined with hybrid-level density functional theory, reveals a shift of 7 ± 3 pm in the top atomic plane. Tunnelling spectroscopy links electronic changes across the phase transition with the electron and hole pockets in the band structure, suggesting a reversible, light-induced annihilation of the topologically protected Fermi arc surface states in the top atomic layer.</p>