Observation of Meissner effect in potassium-doped $p$-quaterphenyl

TL;DR

This study reports the discovery of superconductivity and the Meissner effect in potassium-doped p-quaterphenyl, with critical temperatures up to 120 K, suggesting chain link organic molecules as promising high-temperature superconductor candidates.

Contribution

It demonstrates superconductivity in potassium-doped p-quaterphenyl and links bipolaronic states to the superconducting behavior, expanding the class of organic superconductors.

Findings

Meissner effect observed with Tc up to 120 K

Superconducting phase with Tc of 7.2 K confirmed

Bipolaronic character linked to superconductivity

Abstract

Inspired by the discovery of high temperature superconductivity in potassium-doped $p$-terphenyl, we examine the possibility of superconductivity in $p$-quaterphenyl with one more phenyl ring than $p$-terphenyl. The Meissner effect with critical temperatures ranging from 3.5 K to 120 K is found by the magnetic susceptibility measurements in $p$-quaterphenyl upon doping potassium in the condition of annealing or just pestling. The primary superconducting phase with critical temperature of 7.2 K can be reduplicated in several superconducting samples. In both the annealed and pestled superconducting samples, the observation of bipolaronic character by the Raman scattering measurements reveals the close relationship between bipolarons and superconductivity. The occurrence of superconductivity in potassium-doped $p$-quaterphenyl provides an indication that chain link organic molecules are potential candidates for high temperature superconductors.