Harmonising Symmetry and Spin: Unveiling Giant Rashba Splitting and Diverse Topological Phases in Composite Quantum Materials

We present a systematic theoretical study of ABX-type composite quantum materials crystallizing in non-centrosymmetric hexagonal structures, carried out through high-throughput first-principles density functional theory (DFT) calculations. Approximately 50 candidate systems were screened to explore the interplay between structural symmetry breaking, strong spin–orbit coupling (SOC), and emergent electronic properties. Our investigation reveals a striking coexistence of Rashba spin splitting and topologically nontrivial band topology across this materials family, with Rashba coefficients and band inversions strongly dependent on atomic ordering and chemical composition.

To complement the band-structure analysis, we perform Berry phase calculations, which confirm the topological character of selected states and identify Berry curvature hotspots near avoided crossings. Building upon this, we evaluate the spin Hall conductivity (SHC) and orbital Hall conductivity (OHC) for representative compounds, demonstrating substantial intrinsic values comparable to those in established topological semimetals. These findings point to a strong potential for dissipationless spin and orbital current generation, key ingredients for next-generation spintronic and orbitronic devices.