Electronic Correlation effects in superconducting picene from ab-initio calculations

TL;DR

This study uses ab-initio calculations to show that electron-electron correlations are crucial in potassium-doped picene, influencing its superconducting properties and magnetic states, similar to alkali-doped fullerides.

Contribution

The paper demonstrates the significant role of electron correlations in superconducting picene and predicts an antiferromagnetic state at specific doping levels using hybrid functional calculations.

Findings

Correct gap reproduction for undoped picene

Prediction of antiferromagnetic state at x=3

Similarity to alkali-doped fulleride superconductors

Abstract

We show, by means of ab-initio calculations, that electron-electron correlations play an important role in potassium-doped picene ($K_x$-picene), recently characterized as a superconductor with $T_c = 18K$. The inclusion of exchange interactions by means of hybrid functionals reproduces the correct gap for the undoped compound and predicts an antiferromagnetic state for $x=3$, where superconductivity has been observed. The latter finding is compatible with a sizable value of the correlation strength, in agreement with simple estimates. Our results highlight the similarity between potassium-doped picene and alkali-doped fulleride superconductors.