First-principles spin-transfer torque in CuMnAs|GaP|CuMnAs junctions

We demonstrate that an all-antiferromagnetic tunnel junction with current perpendicular to the plane geometry can be used as an efficient spintronic device with potential high-frequency operation. By using state-of-the-art density functional theory combined with quantum transport, we show that the Neel vector of the electrodes can be manipulated by spin-transfer torque. This is staggered over the two different magnetic sublattices and can generate dynamics and switching. At the same time the different magnetization states of the junction can be read by standard tunneling magnetoresistance. Calculations are performed for CuMnAs vertical bar GaP vertical bar CuMnAs junctions with different surface terminations between the antiferromagnetic CuMnAs electrodes and the insulating GaP spacer. We find that the torque remains staggered regardless of the termination, while the magnetoresistance depends on the microscopic details of the interface.