Voltage-controlled Spin Wave Logic Device: Ring Interferometer

Spin wave logic circuitry transmits information by propagating spin waves along magnetically insulating wave guides. This is less power-consuming than ordinary circuits and is expected to work at THz frequency and room temperature. Logical operations are performed by modulating the interference of spin waves through a phase shifter. A great deal of effort has been devoted to the problem of controlling the phase of spin waves by means of a spatially varying magnetic field, either extrinsic or intrinsic (i.e., by passing the spin wave through a non-uniform magnetic texture). Here we introduce a new approach, which exploits the response of spin waves to an external {\it electric field} via the spin-orbit coupling of this electric field to the electrons that mediate the magnetic interaction. Based on the Heisenberg Hamiltonian modified by spin-orbit coupling, we show how a ring interferometer made of a magnetic insulator (e.g, YIG) can be used to implement NOT logic (and other logic functions) under voltage control.