Spin-current diodes based on germanene and stanene subjected to local exchange fields

Abstract

We theoretically propose a spin-current diode based on germanene and stanene nanoribbons. The results reveal that the germanene or stanene nanoribbon simultaneously under x- and z-direction local exchange fields exhibits excellent rectification characteristics, and that the spin current is blocked in a certain range of spin voltage. The proposed spin-current diodes have three main features: (1) the breakdown voltage of the diodes can be controlled by the strength of exchange fields; (2) the polarity direction of the diodes can be reversed just by adjusting the direction of local exchange fields; and (3) the spin diode effects can be well maintained at 300 K room temperature. All of the results indicate that the proposed germanene and stanene nanosystems are promising candidates for spintronic devices.