The spin Hall resonance effect (SHRE) characterized by a large spin Hall conductivity (SHC) holds immense promise for achieving spin logic and memory devices. However, the identification of a material capable of achieving intrinsic SHRE remains elusive. Herein, we present compelling evidence of intrinsic SHRE within the Bi-based Janus BiXY (X = S, Se and Te; Y = Cl, Br and I) monolayers through first-principles calculations and an effective Hamiltonian model. We attribute the unusual scenario to the warping effect in the Janus monolayers which induces a non-zero out-of-plane spin component, accompanied by additional Rashba degenerate points. Furthermore, we develop a comprehensive effective Rashba Hamiltonian, incorporating high order terms of k to accurately describe the intrinsic SHRE and establish the resilience of this phenomenon in the Janus monolayers. Our study presents a captivating platform for exploring intrinsic SHRE and opens up exciting avenues for the development of novel spintronic devices.

Magnetism has revolutionized important technologies, and continues to bring forth new phenomena in emergent materials and reduced dimensions. Here, using first-principles calculations, we demonstrate that the already-synthesized two-dimensional (2D) Ni-tetracyanoquinodimethane (Ni₂(TCNQ)₂) lattice is a stable ferromagnetism material with multiple spin-polarized Dirac cones. The conical bands in proximity of the Fermi level can be tuned by external tensile strain and show the fourfold degenerate electronic states at the critical tensile strain of ~2.35 %, whose energy dispersion is consistent with 2D Cairo pentagonal lattice. In addition, spin-orbital coupling can open a band gap at the Dirac point of A, leading to topologically nontrivial electronic states characterized by the non-zero Chern number and the edge states of nanoribbon. Our results offer versatile platforms for the realization of massless spintronics with full-spin polarization in 2D Cairo pentagonal Ni₂(TCNQ)₂ Lattice.

A quantum-spin-Hall (QSH) state was achieved experimentally, albeit at a low critical temperature because of the narrow band gap of the bulk material. Twodimensional topological insulators are critically important for realizing novel topological applications. Using density functional theory (DFT), we demonstrated that hydrogenated GaBi bilayers (HGaBi) form a stable topological insulator with a large nontrivial band gap of 0.320 eV, based on the state-of-the-art hybrid functional method, which is implementable for achieving QSH states at room temperature. The nontrivial topological property of the HGaBi lattice can also be confirmed from the appearance of gapless edge states in the nanoribbon structure. Our results provide a versatile platform for hosting nontrivial topological states usable for important nanoelectronic device applications.