Strong Rashba effect induced by mechanical strain in the GeTe monolayer

The GeTe monolayer possesses an AB binary buckled configuration, which can induce intrinsic Rashba spin splitting due to the existence of an internal electric field. However, the electronic structure obtained shows that these splittings are not present near the Fermi level, which makes it unsuitable for practical application. Based on first-principles calculations, we introduce strain engineering to manipulate the Rashba effect. Our results suggest that tensile strain can induce a remarkable Rashba spin splitting of valence band maximum (VBM). With a tensile strain of 10%, the Rashba coefficient can increase to ∼2 eVÅ, which is larger than most 2D Rashba materials. This is because the tensile strain converts the orbital component of the VBM from Te-px (Te-py) to Te-pz states. We propose a spin transistor based on the GeTe monolayer according to its Rashba effect and tunability under strain. Compared to conventional spin field-effect transistors, this transistor can achieve a shorter channel length at the nanometer level, which means that a chip can contain more transistors and integrate it into nanodevices with higher density.