Robust Dirac spin gapless semiconductors in a two-dimensional oxalate based organic honeycomb-kagome lattice

Two-dimensional (2D) ferromagnetic materials with intrinsic and robust spin-polarized Dirac cones are of great interest in exploring exciting physics and in realizing spintronic devices. Using comprehensive ab initio calculations, herein we reveal a family of 2D oxalate-based metal-organic frameworks (MOFs) that possess the desired characteristics. We propose that these 2D oxalate-based MOFs may be assembled by oxalate ions (C₂O₄^2-) and two homo-transition metal atoms. We demonstrate that 2D MOFs of Ni₂(C₂O₄)₃ and Re₂(C₂O₄)₃ are intrinsic Dirac spin gapless semiconductors with linear band dispersion, low energy dissipation and high electron carrier velocity. As robust ferromagnets, they also possess large magnetic moments, large perpendicular magnetic anisotropy, and high Curie temperatures, e.g. 208 K for Ni₂(C₂O₄)₃. In particular, spin-orbit coupling triggers a topologically nontrivial band gap of 143 meV in Re₂(C₂O₄)₃, which is promising to realize the quantum anomalous Hall effect at high temperatures.