Collision of spin current-driven antiferromagnetic Bloch lines

We report on a systematic study of spin current-driven collisions of Bloch lines (BLs) in a biaxial antiferromagnet using micromagnetic simulations and a perturbed sine-Gordon theoretical framework. By analyzing the interplay of damping, spin-torque magnitude, and inertial effects of the Néel order parameter, we identify three distinct collision outcomes. At low BL velocities, mutual annihilation occurs, effectively erasing both topological defects. At intermediate velocities, the BLs reflect elastically, reversing their propagation directions without significant energy loss. For high drive currents that yield large BL velocities, the collisions exhibit a “bursting” phenomenon in which additional BLs are generated, leading to complex multi-soliton dynamics. We further show that the tilting of the domain wall ground state, caused by high spin-torque drive, plays a crucial role in governing the velocity and stability of the colliding BLs. These results highlight key dynamical regimes of antiferromagnetic Bloch lines and suggest potential applications in spin-based memory, logic, and neuromorphic computing, where controlled collisions could enable robust, high-speed manipulation of nanoscale topological information carriers.