Quantum materials with low crystalline symmetry for field-free magnetization manipulation

Spin-orbit torque (SOT) driven control of the magnetization state of a ferromagnet is key to next generation spintronic applications including non-volatile, ultrafast, and energy efficient data storage devices. But field-free deterministic SOT switching of perpendicular magnetization remains a challenge because electric current induced spin polarization in conventional spin source materials, such as heavy metals and topological insulators, is constrained to the film plane due to the system's symmetry. The exploitation of low-crystal symmetries in emergent quantum materials offers a unique approach to achieve SOTs with unconventional forms. In this context, Weyl semimetals (WSMs) with low-crystal symmetries provide a distinct possibility to obtain highly efficient and unconventional charge to spin conversion. We will present our results showing the experimental realization of field-free deterministic switching of a perpendicularly polarized vdW ferromagnet employing WTe2, which is a type-II WSM candidate with low-symmetry crystal structure.