Preserving intrinsic topological states in Cu-dicyanoanthracene via weakly interacting substrate engineering

Abstract

Two-dimensional organic topological insulators (2D-OTIs) face significant challenges in experimental realization due to substrate-induced disruption. We conduct high-throughput density functional theory (DFT) screening of 1825 exfoliable layered semiconductors to identify weakly interacting substrates that preserve the intrinsic topology of a representative 2D-OTI, Cu-dicyanoanthracene (Cu-DCA). Based on lattice matching and adsorption energy as a measure of interaction strength, we identify 11 promising substrates, including H-phase transition metal dichalcogenides, monolayer salts, and ternary chlorides. Crucially, DFT calculations confirm that Cu-DCA retains its Kagome band structure and intrinsic nontrivial topological states on these substrates. Furthermore, molecular dynamics simulations demonstrate feasible Cu-DCA self-assembly on MoSe2 at 300 K, showing sequential bonding of Cu atoms and DCA molecules to expand the islands. This work provides a robust theoretical framework for the experimental synthesis of substrate-stabilized 2D-OTIs, advancing the realization of low-dissipation topological electronics.