Guided motion of a magnetic skyrmion by a voltage-controlled strained channel, and logic applications

Magnetic skyrmions have attracted extensive attention as information carriers for building future power-efficient and ultradense memory or logic devices because of their nanoscale size, topological protection, and current-induced high mobility. The critical issue for realizing the above applications is manipulating skyrmion in a controlled way. Here, we demonstrate a voltage-induced spatial varying channel-like strain in a multiferroic heterostructure to control the trajectory of the current-driven skyrmions. The electromechanical simulation results show that by applying a voltage crossing the piezoelectric thickness, a strain-shaped channel is created as a result of the inverse piezoelectric effect. The voltage-controlled strained channel can modulate the skyrmion Hall effect (SkHE) due to magnetoelastic coupling. We analytically and numerically demonstrated that the compressive and tensive strain inside the channel would lead to a lateral repulsive and attractive force on the skyrmion, respectively, and guide the skyrmion moving straight along the channel. In addition, the skyrmion tunneling effect between two adjacent strained channels with the help of SkHE can be further exploited in developing the demultiplexer (demux) logic gates that work with the voltage-selected region as the selector input and the skyrmion as the information carrier. Furthermore, based on the cascading of demux, the design of programmable logic gates, which were controlled by the voltage-induced strain gates, has been proposed. We also confirmed the operation schematic of the half-adder and full-adder implemented by demux and programmable gates. These results indicated an effective method for guiding the skyrmion motion behavior by voltage-controlled strain, which paved the way to develop skyrmion-based logic gates with reconfigurable and programmable features for information processing and computing systems.