Origin of Rashba Spin Splitting and Strain Tunability in Ferroelectric Bulk CsPbF₃

Abstract

Spin–orbit coupling (SOC) in conjunction with broken inversion symmetry acts as a key ingredient for several intriguing quantum phenomena, viz., Rashba–Dresselhaus (RD) effect. The coexistence of spontaneous polarization and the RD effect in ferroelectric (FE) materials enables the electrical control of spin degrees of freedom. Here, we explore the FE lead halide perovskite CsPbF3 as a potential candidate in the field of spintronics by employing state-of-the-art first-principles-based methodologies, viz., density functional theory (DFT) with semilocal and hybrid functional (HSE06) combined with SOC and many-body perturbation theory (G0W0). For a deeper understanding of the observed spin splitting, the spin textures are analyzed using the k.p model Hamiltonian. We find there is no out-of-plane spin component indicating that the Rashba splitting dominates over Dresselhaus splitting. We also observe that the strength of Rashba spin splitting can be substantially tuned on application of uniaxial strain (±5%). More interestingly, we notice reversible spin textures by switching the FE polarization in CsPbF3 perovskite, making it potent for perovskite-based spintronic applications.

Coupled Spin-Valley, Rashba Effect, and Hidden Spin Polarization in WSi2N4 Family

“…The spin polarization of Bloch states is either parallel or antiparallel to the z -direction leading to the case of PST. These spin textures are different from widely reported locally existing persistent spin textures and are preserved in the whole BZ. − Therefore, the control of Fermi level to a specific part of BZ where PST occurs is not required. These full-zone persistent spin textures (FZPST) can be explained using the symmetry arguments.…”

Structural Symmetry Impressing Carrier Dynamics of Halide Perovskite

“…Bhumla et al. [ 74 ] report that only the in‐plane spin component is detected in the non‐centrosymmetric phase of CsPbF 3 with the R3c space group, indicating that bandgap splitting is dominated by the Rashba effect rather than by the Dresselhaus effect. Moreover, the Rashba parameters increase almost linearly with compressive strain.…”

Full-plane persistent spin textures with cubic order intrinsic and anisotropic band splitting in bulk Lead-free materials

“…λ = 8.13eVÅ 3 , larger than that of around Γ point. The magnitude of splitting in these materials can be further increased by doping of heavier elements with large SOC 45 and introducing strain 17,46 to make its experimental detection more easily accessible (i.e. spin-resolved photoemission spectroscopy).…”

“…However new band splittings happens when the symmetry of a crystal reduces with the strain 47 . Effect of the strain is extensively studied for LR and LD effects 17,46,[48][49][50][51][52] , but effect of strain on PST with PCS is still unknown. Here, we have introduced the out-of-plane strain such that the point group symmetry of crystal remains intact.…”