Prediction of a metallic phase for Cs3Pentacene compound

Abstract

New possible structures for the compounds formed by intercalation of an alkali metal into a molecular crystal formed by polycyclic aromatic hydrocarbon (PAH) molecules have been theoretically searched for. Among them, a crystalline framework in which PAH molecules show a slipped parallel geometry provides an interesting alternative to the usual herringbone arrangement shown by pristine crystal structures of PAHs. While these different crystalline structures are energetically unfavorable for potassium alloying, they are energetically preferred at the highest cesium load (3:1 stoichiometry). The most remarkable feature of the proposed structure is the avoidance of the magnetic instability that leads to insulating phases of herringbone crystals when a 3:1 proportion of metal-Picene is reached. After the evaluation of the corresponding energies of formation, a robust metallic scenario is found for Cs3Pentacene, making it possible the observation of superconductivity.