Controlling structural deformations in WTe2 using THz pulses

Tungsten ditelluride is a layered transition-metal dichalcogenide that crystalizes in a distorted hexagonal net with an orthorhombic unit cell. The lack of inversion symmetry in this phase leads to a predicted new topological semimetal hosting the so-called type-II Weyl points. Here, we use intense THz pulses to trigger a structural deformation in WTe2, and probe its dynamics using an ultrafast electron diffraction (UED) technique. We observe large amplitude interlayer shear oscillations that occur along the in-plane motion between the orthorhombic and monoclinic phases of the material. We will discuss the driving mechanism that can lead to such structural deformation and its implication toward ultrafast THz field control over the topological properties in solids.