Questioning the existence of superconducting potassium doped phases for aromatic hydrocarbons

Satoshi Heguri, Mototada Kobayashi, Katsumi Tanigaki

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)

Abstract

Superconductivity in aromatic hydrocarbons doped with potassium (K) such as K3 [picene (PCN)] and K3 [phenanthrene (PHN)] is found for only armchair-type polycyclic aromatic hydrocarbon. In this paper the thermodynamics of the reaction processes of PHN or anthracene (AN, zigzag type) with K was studied using differential scanning calorimetry and x-ray diffraction. We show that PHN decomposes during the reaction, triggered by hydrogen abstraction, to give metal hydride KH and unknown amorphous. No stable doped phases exist in Kx(PHN) with stoichiometries of x=1-3. However, in the case of AN, a stable doped phase forms. We claim that PHN, which has been reported to be energetically more stable in the ground state than AN by first principle calculations, is unstable upon doping. We also suggest that the superconductivity in K3(PCN) is due to the misinterpretation of experimental data, which actually arises from ferromagnetic impurities. We have never detected the superconductivity above 2 K in these compounds. The superconductivity in both Kx(PHN) and Kx(PCN) is concluded to be highly questionable.

Original languageEnglish
Article number014502
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume92
Issue number1
DOIs
Publication statusPublished - 2015 Jul 7

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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