Paving the way for Boolean logic by skyrmion based programmable logic devices

Skyrmions enable ultralow-power nonvolatile logic gate designs because of their nanoscale dimensions, current-driven motion, and topological protection. The logic inverter (NOT) gate is an important component in digital spintronics employing skyrmions. Despite recent computational and practical demonstrations, a skyrmion-based low-power, wideband, and cascadable inverter gate is yet to be developed. The systematic design and analysis of an inverter gate is critical for scalable skyrmion-based logic circuits. Here, we demonstrate that the inverter gate can operate with direct current drive, wide bandwidth, low energy consumption (~1350 k_BT/bit at room temperature), small footprint (~300 nm) with dimensions feasible for nanofabrication, no or very limited external magnetic field, cascadability and room temperature thermal stability. 2D room temperature semiconductor or insulating magnetic materials could also help eliminate Joule dissipation. These findings imply that the inverter gate might be cascaded and operated without loading or thermal drift inside larger-scale digital spintronic circuits. By combining the inverter with AND and OR gates in a similar functional, thermally robust, and cascadable way, any arithmetic or Boolean logic capabilities may be implemented.