MANA International Symposium 2026

MANA
menu

Poster QM-12

Interface-Induced Rashba Spin Splitting in a Transition-Metal Monochalcogenide/Dichalcogenide Heterostructure

Souren Adhikary

Author

Souren Adhikary, Tomoaki Kameda, Katsunori Wakabayashi

Affiliation

Qubit Materials Design Group, MANA, NIMS

URL

https://samurai.nims.go.jp/profiles/wakabayashi_katsunori

Biography

Souren Adhikary: Postdoctoral Researcher at NIMS
Tomoaki Kameda: PhD Student at Kwansei Gakuin University
Katsunori Wakabayashi: Group Leader, Quantum Materials Design Group at MANA, NIMS

Abstract

Spin-orbit coupling (SOC) has attracted significant attention in materials science owing to its potential applications in next-generation information technologies [1-2]. Mirror symmetry breaking combined with strong SOC can induce the Rashba effect [3]. Using density functional theory, we demonstrate that a vertical heterostructure composed of monolayer NiTe (transtionmetal monochalcogenide) and NiTe2 (transition-metal dichalcogenide) exhibits a giant Rashba spin splitting, characterized by a large Rashba parameter of 1.318 eV·Å.

Figure for Souren Adhikary abstract
Fig. 1. (a) Side view of NiTe/NiTe2 heterostructure. The built-in dipole moment P is indicated by a vertical arrow. (b) Electronic band structure of NiTe/NiTe2 system in the presence of SOC. Rashbasplit bands are highlighted by the green box. A schematic illustration of the Rashba splitting is indicated by the zoom view. The Rashba parameter is evaluated as 𝛼R = 2𝐸R/Δ𝑘R. (c) Spin current conductivity for in-plane spin components induced by linearly polarized light. (d) Schamtic presentation of spin conductivities for different spin components.
Although the individual monolayer preserves both mirror and inversion symmetries, stacking them into a vertical heterostructure breaks both symmetries, due to the intrinsic structural asymmetry at the interface (see Fig.(a)). This symmetry breaking produces a substantial interfacial dipole moment (P), which drives the large Rashba effect. Notably, the Rashba-split bands appear close to the Fermi energy (≈ 0.1 eV below), making them particularly relevant for device applications (see Fig.(b)). In addition, we investigate the optical spin response of the NiTe/NiTe2 eterostructure and demonstrate efficient spin-current generation under linearly polarized light at relatively low photon energies (see Fig.(c) & (d)) [4-5].
Furthermore, we predict that the proposed interface-engineering strategy is applicable to a broader family of transition-metal chalcogenides. In particular, Co-based counterparts and hybrid Ni/Co heterostructures are also predicted to exhibit pronounced Rashba spin splitting.

References

  1. S. Wolf et al., Science, 294, 1488 (2001), DOI: 10.1126/science.1065389
  2. X. Xu et al., Nat. Phys., 10, 343 (2014), DOI: https://doi.org/10.1038/nphys2942
  3. A. Manchon et al., Nat. Mater., 14, 871 (2015), DOI: https://doi.org/10.1038/nmat4360
  4. R. Habara and K. Wakabayashi, Phys. Rev. B 103, L161410 (2021),
  5. DOI: https://doi.org/10.1103/PhysRevB.103.L161410
  6. S. Adhikary, T. Kameda and K. Wakabayashi (submitted).
NIMS
MANA
JSPS
JST ASPIRE