Colossal Spin Transfer Torque Effect on Skyrmion along the Edge

We study by the micromagnetic simulations the skyrmion motion along the edge driven by the current transverse to it. We found that (i) the velocity is enhanced by the factor of ∼1/α (α: the Gilbert damping) with the maximum value determined only by the confining force from the edge, (ii) the inertia appear due to the confining potential with the coordinate perpendicular to the edge playing the role of the kinetic momentum, and (iii) the collision between the two skyrmions is almost elastic without causing any internal distortions.