Metal-intercalated aromatic hydrocarbons: a new class of carbon-based superconductors

Kubozono, Yoshihiro; Mitamura, Hiroki; Lee, Xuesong; He, Xuexia; Yamanari, Yusuke; Takahashi, Yosuke; Suzuki, Yoshitake; Kaji, Yumiko; Eguchi, Ritsuko; Akaike, Kouki; Kambe, Takashi; Okamoto, Hideki; Fujiwara, Akihiko; Kato, Takashi; Kosugi, Taichi; Aoki, Hideo

doi:10.1039/c1cp20961b

Cited by 206 publications

(239 citation statements)

References 99 publications

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“…Potassium enters within the PAH herringbone structure (intralayer doping) where there is space enough for three dopant atoms. This was the consensus immediately after the discovery of superconducting properties of K-doped picene [1, [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Structural and electronic changes of pentacene induced by potassium doping

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Vergés

2017

Phys. Rev. B

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Potassium is introduced into the crystalline herringbone structure of pentacene searching for a compound showing metallic electronic transport properties and, hopefully, superconductivity at small enough temperatures. Several possible structures for stoichiometric KPentacene (1:1), K 2 Pentacene (2:1), and K 3 Pentacene (3:1) compounds are theoretically investigated. Detailed densities of states for all of them are presented. As a more prominent result, a new monoclinic structure has been stabilized for the potassium richer material that could correspond to the recently synthesized superconducting phase of K 3 Pentacene. Although energetically unfavorable, it is the only metallic candidate found to date.

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Section: Introductionmentioning

confidence: 99%

Structural and electronic changes of pentacene induced by potassium doping

Guijarro

Vergés

2017

Phys. Rev. B

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“…The pioneering work of Mitsuhashi et al [1] showed superconductivity of potassium-intercalated picene at 7 or 18 K, depending on sample processing. Later, other PAH crystals formed by coronene [2], phenanthrene [3], and dibenzopentacene [4] have also shown superconducting properties according to the temperature behavior of magnetic susceptibility. Doping with group 2 elements is also possible [5].…”

Section: Introductionmentioning

confidence: 99%

Role of potassium orbitals in the metallic behavior ofK3picene

et al. 2014

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Detailed electronic structure calculations of picene clusters doped by potassium modeling the crystalline K 3 picene structure show that while two electrons are completely transferred from potassium atoms to the lowest-energy unoccupied molecular orbital of pristine picene, the third one remains closely attached to both material components. Multiconfigurational analysis is necessary to show that many structures of almost degenerate total energies compete to define the cluster ground state. Our results prove that the 4s orbital of potassium should be included in any interaction model describing the material. We propose a quarter-filled two-orbital model as the most simple model capable of describing the electronic structure of K-intercalated picene. Precise solutions obtained by a development of the Lanczos method show low-energy electronic excitations involving orbitals located at different positions. Consequently, metallic transport is possible in spite of the clear dominance of interaction over hopping.

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“…7 Reaction of potassium with picene (C22H14), a phenacene composed of five fused benzene rings, has been reported to afford superconductivity at 18 K. 8 Superconductivity in other alkali-metal polyaromatic hydrocarbons (PAHs) was subsequently reported in phenanthrene-, dibenzopentacene-and coronene-based materials, with the highest reported Tc of 33 K claimed 2 in potassium-doped 1,2:8,9-dibenzopentacene. [9][10][11] Despite the significant interest in these materials, to date no crystal structure has been determined for any of the alkali-metal PAH systems. This structural information is a prerequisite for materials design and for understanding of both physical properties and reaction chemistry.…”

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confidence: 99%

“…[9][10][11] Despite the significant interest in these materials, to date no crystal structure has been determined for any of the alkali-metal PAH systems. This structural information is a prerequisite for materials design and for understanding of both physical properties and reaction chemistry.…”

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Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids

et al. 2017

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Alkali metal intercalation into polyaromatic hydrocarbons (PAHs) has been studied intensely following reports of superconductivity in a number of potassium-and rubidium-intercalated materials. There are however no reported crystal structures to inform understanding of the chemistry and physics because of the complex reactivity of PAHs with strong reducing agents at high temperature. Here we present the synthesis of crystalline K2Pentacene and K2Picene by a solid-solid insertion protocol that uses potassium hydride as a redox-controlled reducing agent to access the PAH dianions, enabling determination of their crystal structures. In both cases, the inserted cations expand the parent herringbone packings by reorienting the molecular anions to create multiple potassium sites within initially dense molecular layers, and thus interact with the PAH anion π-systems. The synthetic and crystal chemistry of alkali metal intercalation into PAHs differs from that into fullerenes and graphite, where the cation sites are pre-defined by the host structure.Reaction of alkali and alkaline earth metals with carbon-based molecular solids has been extensively studied in the search for novel magnetic and electronic properties, with a particular focus on superconductivity. [1][2][3][4][5][6] For example, alkali metal intercalation into solid C60 produces A3C60 superconductors, with Tc as high as 38 K for Cs3C60 at 7 kbar. 6 In these materials, cations occupy the interstitial voids that already exist in the host e.g., in the fcc lattice of C60 (Figure 1). 7 Reaction of potassium with picene (C22H14), a phenacene composed of five fused benzene rings, has been reported to afford superconductivity at 18 K. 8 Superconductivity in other alkali-metal polyaromatic hydrocarbons (PAHs) was subsequently reported in phenanthrene-, dibenzopentacene-and coronene-based materials, with the highest reported Tc of 33 K claimed 2 in potassium-doped 1,2:8,9-dibenzopentacene. [9][10][11] Despite the significant interest in these materials, to date no crystal structure has been determined for any of the alkali-metal PAH systems. This structural information is a prerequisite for materials design and for understanding of both physical properties and reaction chemistry.Picene, like many other PAHs (including molecules such as phenanthrene 12 which is reported to afford superconductivity on cation insertion), crystallises in the herringbone structure, 13 with layers consisting of two parallel one-dimensional chains of molecules with opposing inclinations defined by an intermolecular angle, ω, of 57.89(7)° (Supplementary Figure 1). 14 The largest voids in the structure are located between the picene layers, adjacent to the saturated C-H bonds and far from the electron density of the PAH π-systems ( Figure 1a). This contrasts with C60, where the octahedral and tetrahedral voids in the fcc lattice are adjacent to the conjugated π-electron system (Figure 1b Pentacene is the linear isomer of picene, and also adopts the herringbone structure, 16 with ω = 52...

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Metal-intercalated aromatic hydrocarbons: a new class of carbon-based superconductors

Cited by 206 publications

References 99 publications

Structural and electronic changes of pentacene induced by potassium doping

Structural and electronic changes of pentacene induced by potassium doping

Role of potassium orbitals in the metallic behavior ofK3picene

Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids

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