The first-principles investigations on magnetic ground-state in Sm-doped phenanthrene

Abstract

Based on the density functional theory plus the effective Coulomb repulsion U, we have investigated the crystal structure, electronic properties and magnetic characteristics in Sm-doped phenanthrene, recently characterized as a superconductor with Tc∼5−6 Kelvin. Calculated total energies of different magnetic states indicate that Sm-doped phenanthrene is stable at the ferromagnetic ground-state. Considered the strong electronic correlations effect due to the intercalation of Sm-4f electrons, we found that the Sm-4f contributes to the Fermi surface together with C-2p, which is different from K-doped phenanthrene. Compared with alkali-metal-doped phenanthrene, Sm atom has larger local magnetic moment, which suppresses the superconductivity in conventional superconductors. Our results indicate that the electron-electron correlations play an important role in superconductivity of Sm-doped phenanthrene.

Structural and Bonding Characteristics of Potassium-Doped p-Terphenyl Superconductors

“…So far, the highest T c reached is 33.1 K in PAH superconductors, which was obtained in K-doped 1,2;8,9-dibenzopentacene . However, previous theoretical studies showed that PAH superconductors usually exhibit the antiferromagnetic (AFM) ground state − and exist the strong electronic correlation effects, − indicating that the superconducting mechanism is complicated in aromatic hydrocarbons. Our theoretical predictions have argued that electronic correlations or pressure could enhance high T c in aromatic hydrocarbons.…”