Large out-of-plane spin orbit torque generated by topological materials

Field-free switching of magnets in Spin-Orbit-Torque Random Access Memory (SOT-MRAM) requires large out-of-plane spin-orbit torques (SOTs). Weyl semimetals (WSMs), particularly Type-II WSMs with tilted Weyl cones, are potential candidates for generating such torques due to their strong spin-momentum locking. In this work, we use the tight-binding Nonequilibrium Green's Function (TB-NEGF) method to calculate the SOTs generated by WSMs, considering Hamiltonians for both minimal models and realistic materials. We also illustrate the potential of these materials for designing of a strained weyl-semimetal spin-orbit torque random access memory (SWSM-SOTRAM) bit cell comprising a piezoelectric/magnet (gating)/Weyl semimetal/magnet (storage) heterostructure that can be used in low-power in-memory computing.