Investigation on synthesis and physical properties of metal doped picene solids

Abstract

We report electronic structure and physical properties of metal doped picene as well as selective synthesis of the phase exhibiting 18 K superconducting transition. First, Raman scattering is used to characterize the number of electrons transferred from the dopants to picene molecules. The charge transfer leads to a softening of Raman scattering peaks, which enables us to determine the number of transferred electrons. From this we have identified that three electrons are transferred to each picene molecule in the superconducting doped-picene solids. Second, we report the pressure dependence of Tc in 7 and 18 K phases of K3picene. The 7 K phase shows a negative pressure-dependence, while the 18 K phase exhibits a positive pressure-dependence which cannot be understood with a simple phonon mechanism of BCS superconductivity. Third, we report a new synthesis method for superconducting K3picene by a solution process with monomethylamine, CH3NH2. This method enables one to prepare selectively the K3picene sample exhibiting 18 K superconducting transition. The discovery of suitable way for preparing K3picene with Tc = 18 K may facilitate clarification of the mechanism of superconductivity.

arXiv comment18 pages, 2 tables, 8 figures

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Cited by in corpus (5)

• Absence of metallicity in K-doped picene: Importance of electronic correlations
• A combined experimental and computational study of the pressure dependence of the vibrational spectrum of solid picene C_22H_14
• Ba${}_2$phenanthrene is the main component in the Ba-doped phenanthrene sample
• Theory of metal-intercalated phenacenes: Why molecular valence 3 is special
• The role of potassium orbitals in the metallic behavior of K3picene