Gate-Tunable Spin xor Operation in a Silicon-Based Device at Room Temperature

Room-temperature operation of a spin exclusive-or (xor) gate is demonstrated in lateral spin-valve devices with nondegenerate silicon ($\mathrm{Si}$) channels. The spin xor gate is a fundamental part of the magnetologic gate that enables reconfigurable and nonvolatile nand or or operation in one device. The device for the spin xor gate consists of three iron ($\mathrm{Fe}$)/cobalt ($\mathrm{Co}$)/magnesium oxide ($\mathrm{Mg}\mathrm{O}$) electrodes (i.e., two input electrodes and one output electrode). Spins whose spin angular momentum corresponds to the binary input 1 or 0 are injected into the $\mathrm{Si}$ channel from the input electrodes. The spin-drift effect is controlled by a lateral electric field in the $\mathrm{Si}$ channel to adjust the spin-accumulation voltages under two different parallel configurations, corresponding to (1, 1) and (0, 0), so that they exhibit the same value. As a result, the spin-accumulation voltage detected by the output electrode exhibits three different voltages, represented by an xor gate. The one-dimensional spin-drift--spin-diffusion model clearly explains the xor behavior obtained. Charge-current detection of the spin xor gate is also demonstrated. The detected charge current has a maximum of 1.67 nA, the highest value in spin xor gates reported thus far. Furthermore, gate-voltage modulation of the spin xor gate is also demonstrated, which enables operation of multiple magnetologic gate devices.