Stability of spin XOR gate operation in silicon based lateral spin device with large variations in spin transport parameters

We investigate stability of the spin exclusive or (XOR) gate operation in silicon(Si) -based lateral spin devices whose spin transport properties have large variations. The optimum charge current, I0, for the spin XOR gate operation is calculated by using the one dimensional spin-drift-diffusion model with variable spin polarization, interface resistance of the ferromagnetic contact, channel length and channel conductivity. I0 is strongly modulated by changing the spin transport parameters particularly under the condition with small spin polarization and short channel length. In contrast, I0 shows constant value irrespective of the interface resistance of one ferromagnetic contact under spin extraction condition. Our results provide a device design guideline for the robust spin XOR gate operation.