Magnetic properties of polyacetylene: Exploring electronic correlation effects through first-principles modeling

Abstract

Polyacetylene, a simple yet fascinating polymer, has attracted significant interest due to its unique electronic properties. However, the influence of electronic correlation effects within density functional theory (DFT) on polyacetylene has not been fully explored on an ab initio basis. Using a range of exchange–correlation functionals – including GGA, meta-GGA, and hybrid functionals – we demonstrate that correlation effects may stabilize a magnetic moment on the $\pi$-conjugated carbon $p$ orbitals. Our study highlights the complex physics of polyacetylene and suggests intriguing parallels with the parent compound of the nickelate family, LaNiO${}_2$, which hosts competing low-energy stripe phases similar to those observed in doped cuprates.