Giant Rashba effect at the topological surface of PrGe revealing antiferromagnetic spintronics

Soma Banik,A K Sinha,S K Deb,Nathan Beaulieu,Jun Fujii,Azzedine Bendounan,A Thamizhavel,D M Phase,A Arya,Pranab Kumar Das,Ivana Vobornik,P U Sastry

doi:10.1038/s41598-017-02401-z

Abstract

Rashba spin-orbit splitting in the magnetic materials opens up a new perspective in the field of spintronics. Here, we report a giant Rashba spin-orbit splitting on the PrGe [010] surface in the paramagnetic phase with Rashba coefficient αR = 5 eVÅ. We find that αR can be tuned in this system as a function of temperature at different magnetic phases. Rashba type spin polarized surface states originates due to the strong hybridization between Pr 4f states with the conduction electrons. Significant changes observed in the spin polarized surface states across the magnetic transitions are due to the competition between Dzyaloshinsky-Moriya interaction and exchange interaction present in this system. Presence of Dzyaloshinsky-Moriya interaction on the topological surface give rise to Saddle point singularity which leads to electron-like and hole-like Rashba spin split bands in the bar{{boldsymbol{Z}}}^{prime} -bar{{boldsymbol{Gamma }}}-bar{{boldsymbol{Z}}} and bar{{boldsymbol{X}}}^{prime} -bar{{boldsymbol{Gamma }}}-bar{{boldsymbol{X}}} directions, respectively. Supporting evidences of Dzyaloshinsky-Moriya interaction have been obtained as anisotropic magnetoresistance with respect to field direction and first-order type hysteresis in the X-ray diffraction measurements. A giant negative magnetoresistance of 43% in the antiferromagnetic phase and tunable Rashba parameter with temperature makes this material a suitable candidate for application in the antiferromagnetic spintronic devices.

Highlights

One of the main challenges in the field of spintronics is to manipulate the spin structures by electric and spin currents
The effective magnetic moment is related to the magnetocrystalline anisotropy (MCA), which is intrinsically linked to the SO interaction
We report that the Rashba type SO splitting observed on the topological surface of PrGe [010] single crystal is due to the fact that the system behaves like a weak ferromagnetic system which is associated with the spin-canting antiferromagnetic coupling between the Pr atoms

Summary

Introduction

One of the main challenges in the field of spintronics is to manipulate the spin structures by electric and spin currents. Detail band structure study at different temperatures is performed to understand the nature of the spin split bands across the magnetic transitions.

Results

Conclusion