铁磁电极单层二硫化钼纳米带量子结构中的自旋开关效应和巨磁阻

Spin-switching effect and giant magnetoresistance in quantum structure of monolayer MoS_(2) nanoribbons with ferromagnetic electrode

采用三带紧束缚模型和非平衡格林函数的方法理论研究了铁磁电极单层之字形二硫化钼纳米带量子结构中的自旋电子输运性质.结果发现,由于铁磁电极的磁交换作用与散射区域电场共同影响,可获得能量依赖的100%自旋极化,得到纯的自旋流.这表明在该结构通过调控入射能可以实现自旋电子开关效应.此外,还发现当电导完全自旋极化时,磁交换场强度可以对巨磁阻效应进行有效的调控.该工作可为基于单层二硫化钼纳米带设计巨磁阻器件以及自旋过滤器提供理论参考.

Spintronics is a new type of electronics based on electron spin rather than charge as the information carrier,which can be stored and calculated by regulating and manipulating the spin.The discovery and application of the giant magnetoresistance effect opens the door to the application of electron spin properties.Realizing ondemand control of spin degree of freedom for spin-based devices is essential.The two-dimensional novel material,monolayer transition metal dichalcogenide(TMD)(MoS_(2) is a typical example from the family of TMD materials),has become an excellent platform for studying spintronics due to its novel physical properties,such as direct band gap and strong spin-orbit coupling.Obtaining high spin polarization and achieving controllability of degrees of freedom are fundamental problems in spintronics.In this paper,we construct the monolayer zigzag MoS_(2) nanoribbon quantum structure of electrically controlled ferromagnetic electrode to solve this problem.Based on the non-equilibrium Green’s function method,the regulation of the magnetic exchange field and electrostatic barrier on the spin transport in parallel configuration and anti-parallel configuration are studied.It is found that in the parallel structure,spin transport is obviously related to the magnetic exchange field,and 100%spin filtering can occur near the Fermi energy level to obtain pure spin current.When an additional electric field is applied to the middle region,the spin filtering effect is more significant.Therefore,the spin switching effect can be achieved by regulating the incident energy.In addition,it is also found that within a specific energy range,electrons in the parallel configuration are excited to participate in transport,while electrons in the anti-parallel structure are significantly inhibited.Consequently,a noticeable giant magnetoresistance effect can be obtained in this quantum structure.Moreover,it can be seen that the magnetic exchange field strength can effectively modulate the giant magnetoresistance effect.These results provide valuable theoretical references for the development of giant magnetoresistance devices and spin filters based on monolayer zigzag MoS_(2) nanoribbons.