Proximity Effect Induced Spin Injection in Semimetal on Magnetic Insulator based Two Dimensional Heterostructure
Mayuri Bora, Sushant Kumar Behera, Pritam Deb
Advanced Functional Material Laboratory (AFML), Department of Physics, Tezpur University (Central University), Tezpur-784028, India.
Email address: mayu219[at]tezu.ernet.in
Abstract: Pure spin current generation by the use of insulating magnetic two dimensional materials is preferred due to its potential application in low energy dissipation information transport and processing [1]. The spin current generation is usually achieved at the interface between a strong spin-orbit coupling semimetal (SM) sheet and a ferromagnetic (FM) insulator via spin injection or pumping [2-3]. Understanding the structure and magnetism of the SM/FM heterostructure interface is of crucial importance for both the understanding and the improvement of spin current generation. Moreover, spin-dependent properties of two dimensional heterostructures, controlled by external electric field, is one of the most interesting phenomena in current materials research due to the promise of new device functionalities [4]. One of the paradigms in this approach is to electrically toggle the spin polarization of carriers injected into a nonmagnetic semimetal using ferromagnetic polarization as a control parameter. We investigate the effect of ferromagnetic polarization of CrBr3 on the spin-polarized transmission across the semimetal graphene interface of CrBr3/Graphene heterostructure following ab initio density functional calculations. Our study reveals that, in this heterostructure system, the interface transmission is fully spin polarized and that ferromagnetic polarization reversal leads to a change in the transport spin polarization upto 48%. Computational model calculations demonstrate that this is a general effect for ferromagnetic-semimetal hetero systems and, furthermore, that ferromagnetic modulation can reverse the sign of spin polarization from positive to negative depending upon spin orientation. The predicted effect provides an in-depth mechanism to electrically control spin injection in ferromagnetic-semimetal heterostructure based spintronics devices.
References
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[4] Xiaohui, L. et al. Electric Control of Spin Injection into a Ferroelectric Semiconductor. Phys. Rev. Lett. 2015, 114, 046601.