Presentation Information
[22p-12K-9]Giant Rashba Spin-Orbit Coupling Parameter in Cu/Cu3N Polar Superlattice
〇(PC)Yusuf Wicaksono1, Koichi Kusakabe2, Seiji Yunoki3, Sadamichi Maekawa3,4,5 (1.RIKEN CPR, 2.Univ. Hyogo, 3.RIKEN CEMS, 4.Kavli Institute, 5.JAEA ASRC)
Keywords:
spintronics,Rashba effect,Interface
The Rashba effect is a type of spin-orbit (SO) splitting that occurs on surfaces and interfaces where the inversion symmetry is broken. The two main contributions to creating large Rashba SO spin splitting are strong atomic SO coupling (SOC) interaction and an internal electric field along the surface/interface normal. The strength of Rashba SOC is commonly improved by introducing materials based on heavy elements, such as those found in Bi on the Ag(111) or BeTeI surfaces, which have Rashba parameters of 3.05 and 4.30 eVA, respectively. However, creating Rashba SOCs as high as those of heavy-element-based materials in nonheavy-element materials while optimizing the internal electric field has been challenging. In this theoretical study, we present a new strategy to create a giant Rashba SOC effect with Rashba parameters of 3.80 eVA on a Cu/Cu3N superlattice, which is a superlattice interfacing a simple light metal with its nitride. The giant Rashba parameter comes from optimizing the internal electric field that comes from the polarity, interface, and superlattice structure, which gives a constructive cummulative effect. Furthermore, two-dimensional spin-momentum locking was observed. Our proposal was confirmed through first-principles calculations. This strategy provides a powerful way to design the next generation of spintronics without the use of heavy components.