Tunable electronic structure and Rashba spin splitting of WSe2/WS2 van der Waals heterostructure via strain and electric-field

Abstract

Suitable band structure, effective carrier separation and spin-charge locking are critical for further development and application of nanoscale spintronic devices. In this work, the effects of in-plane biaxial strain and electric field on the electronic structures and Rashba spin splitting of WSe 2 /WS 2 van der Waals heterostructure are investigated by the first principles calculations. The results show that considering the SOC effect, an observable Dresselhaus spin splitting of 424.5 meV and Rashba spin splitting can be observed at the K and Γ point in the valence band, respectively. At the same time, unexpected circle-type Berry curvature occurs due to a broken mirror structure for the WSe 2 /WS 2 heterostructure. A largest Rashba parameter α R with 0.503 eV Å can be achieved at the strain of −4% and the positive electronic field tend to weaken the strength of Rashba spin splitting. The linear Rashba spin splitting strength of WSe 2 /WS 2 heterostructure is tried to clarify, and coexistence of valley-contrasting property and Rashba effect enables spintronics and valleytronics application can be achieved. These results provide a way to engineer the electronic structure and Rashba spin splitting of WSe 2 /WS 2 heterostructure and open up the possibilities for exploring spin logic electronic devices as well as valleytronic devices. • Effects of strain and electric field on the electronic structures of WSe2/WS2van der Waals heterostructure are studied. • The WSe 2 /WS 2 heterostructure exhibits type-II band alignment and tunable Rashba spin splitting. • Unexpected circle-type Berry curvature occurs due to broken mirror structure. • A largest Rashba parameter α R of 0.507 eV Å can be obtained at the strain of −4%.