Tautomerization Makes Topological Phase Transition in 2D Organometallic Lattices

Abstract

AbstractThe investigation into approaches for achieving reversible control of topological phase transitions has attracted substantial research interest. So far, several system‐dependent physical control methods are developed, while a chemical strategy for efficient regulation of topological properties is still lack. Here, this study presents a chemical means to achieve reversible topological control in 2D organometallic lattices by introducing the lactam‐lactim tautomerization modules in the organic linkers. The strategy is validated in the theoretically designed 2D hexagonal framework with planar tricoordinated Co as nodes and 2,2′‐bithiazole derivatives as organic linkers, which transforms from a ferrimagnetic half metal with a local gap featuring Chern number of +1 to a ferromagnetic Chern insulator possessing Chern number of −1 after lactam‐lactim tautomerization. Simultaneously, a flip in the spin polarization of charge carriers between the two lattice tautomers is also observed.