WSe2 based Valley-Coupled-Spintronic Devices for Low Power Non-Volatile Memories

We propose valley-coupled spintronic devices based on monolayer WSe ₂ that utilize Valley-Spin Hall (VSH) effect to switch nano-magnets. The unique features of the proposed device are (a) the ability to switch magnets with perpendicular magnetic anisotropy (PMA) and (b) an integrated gate that can modulate the charge/spin current (IC/IS) flow. The former attribute results in high energy efficiency (compared to the Giant-Spin Hall (GSH) effect based devices with in-plane MA (IMA) magnets). The latter feature averts the need for additional access transistor in a memory array leading to high integration density. We experimentally measure the gate controllability of the current as well as the non-local resistance associated with VSH effect. Based on the measured data, we develop a simulation framework (using physical equations) to propose and analyze single-ended and differential VSH effect based magnetic memories (VSH-MRAMs). Compared to GSH-MRAMs, VSH-MRAMs achieve 45% lower write power (at iso-write time), 10% lower read power (at iso-sense margin) and 48% lower area.