Density functional calculations of the electronic structure and magnetic properties of the hydrocarbon K3picene superconductor near the metal-insulator transition

TL;DR

This study uses density functional theory to explore the electronic and magnetic properties of K3picene, a hydrocarbon superconductor, revealing its proximity to a Mott transition and details of its electronic structure.

Contribution

It provides the first detailed electronic structure and magnetic property analysis of K3picene, highlighting its near-Mott transition and the nature of its active bands for superconductivity.

Findings

K3picene undergoes a metal-insulator transition with 5% volume increase.

Active bands for superconductivity are hybridized LUMO and LUMO+1 orbitals.

K3picene is near the Mott transition based on U/W ratio.

Abstract

We have investigated the electronic structures and magnetic properties of of K3picene, which is a first hydrocarbon superconductor with high transition temperature T_c=18K. We have shown that the metal-insulator transition (MIT) is driven in K3picene by 5% volume enhancement with a formation of local magnetic moment. Active bands for superconductivity near the Fermi level E_F are found to have hybridized character of LUMO and LUMO+1 picene molecular orbitals. Fermi surfaces of K3picene manifest neither prominent nesting feature nor marked two-dimensional behavior. By estimating the ratio of the Coulomb interaction U and the band width W of the active bands near E_F, U/W, we have demonstrated that K3picene is located in the vicinity of the Mott transition.