Electrical Spin Injection In ZrTe₅ Nanowire Spin-valve

Topological Dirac materials usually own a topological band structure with a protection of time inversion symmetry,and therefore they exhibit the strong anti-backscattering property.The recent discovery of transition metal pentatelluride ZrTe5 is knew as a kind of topological Dirac semimetal,and it presents a high mobility for its layered structure.In addition,it’s spin distinguished topological surface state can significantly reduce the electron’s scattering.Overall,topological Dirac materials ZrTe5 possess a huge potential in applications such as low-energy-consumption transport and future spintronic.The research on spin-related injection and detection among nanowire devices has been always in progress.For a long time,semiconductors served as the main nanowire materials in researches,and in recent years,it extended to the field of topological insulators.However,no one has yet studied on spin injection and detection of ZrTe5.ZrTe5 material,which owns semi-metal properties together with topological properties,remains essential to the researches of devices.In this paper,ZrTe5 nanowire is the main research material,and we fabricated the spin-valve structured device through well-operated micro-machining equipment.With the help of low temperature lock-in transport measurement system,we detected different magnetic resistance changes in both non-local and local measurement modes.1.In the case of non-local measurement,we believe the MR curved signals come from ZrTe5 topological surface state since the spin-momentum-locking contribution.In this measurement structure,we analyzed the reason why changing the direction of current direction does not change the resistance stage’s,and we recognized it is the diffusion current from the injector that influenced the condition of spin momentum locking.We did not find any significant changes in magnetic resistance in the compared group(Au)nanowires.At the same time,we measured stable signals at different temperatures.2.In local mode,we also measure the resistance platform signal similar to the hysteresis loop,and we found that the signal reversed with the current direction.Further,we determine it derived from a clear topological surface state conducting spin polarization.3.We prove that the "bimodal" magnetoresistance(MR)curves in local mode come from the anisotropic magnetoresistance(AMR)characteristics of ferromagnetic electrodes.During the research,in order to confirm our suspect,we fulfilled the controlled trials.Replacing the ZrTes material with gold(Au),we fabricated the same spin valve device,and then we detected the magnetic resistance with the same method.We found that the change rate of the magnetoresistance is inversely proportional to the total resistance of the whole measurement circuit,i.e.,the change of magnetoresistance is quite steady,which means the signals simply relate to the anisotropic magnetoresistance(AMR)of the ferromagnetic electrode.