Magnetic two-dimensional organic topological insulator: Au-1,3,5-triethynylbenzene framework

Based on first-principles calculations, we demonstrate that the recently-synthesized 2D organometallic framework consisting of Au atoms and 1,3,5-triethynylbenzene (Au-TEB) is a magnetic 2D organic topological insulator (OTI). The charge transfer and covalent bonding character lead to ferromagnetism and half-metallicity in the framework, and the weak spin-orbit coupling (SOC) of C p_z orbitals mediated by Au d orbitals opens modest bandgaps in the vicinity of the Fermi level. Moreover, using tight-binding model simulations, we further characterize the nonzero Chern number and edge states of Au-TEB to confirm its topological nontriviality that remains intact when the framework is supported on an insulating substrate, and applying an external strain can increase the magnitude of SOC gaps, leading to an enhanced topological nontriviality. Our results suggest that the Au-TEB organometallic framework is promising for the potential applications in quantum spintronics with the merits of low cost and easy synthesis.