Skyrmions and antiskyrmions from current-induced boundary instabilities

We study generation and dynamics of skyrmions and antiskyrmions using current-induced torques at interfaces between adjacent regions with differing properties such as DMI (Dzyaloshinskii-Moriya interaction), anisotropy, exchange, etc.. The generation of skyrmions and antiskyrmions can be interpreted as a current-induced Doppler shift acting on the magnons localized at the interface. These localized modes are analyzed by using the Bogoliubov-de-Gennes Hamiltonian written for magnons. We confirm our theoretical predictions using micromagnetics simulations, where we observe that a current pulse closes the magnon band gap, leading to instabilities in the magnetic texture at the interface between different regions. From micromagnetic simulations, we observe that the closure of the magnon band gap effectively causes the system to form skyrmions and/or antiskyrmions, depending on the type of DMI present.