Superconductivity at 5 K in alkali-metal-doped phenanthrene

Wang, X. F.; Liu, R. H.; Gui, Zhigang; Xie, Yurong; Yan, Yiqing; Ying, Jianjun; Luo, X. G.; Chen, X.H.

doi:10.1038/ncomms1513

Cited by 208 publications

(208 citation statements)

References 32 publications

(42 reference statements)

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“…1 lower panel. The latter have received increasing attention recently due to the observation of superconductivity in alkali doped hydrocarbon crystals, among them picene, with relatively high transition temperatures to the superconducting state [10][11][12][13][14][15]. In all cases the molecules in the solid arrange in a herringbone manner which is typical for many aromatic hydrocarbon molecular solids and can be seen as a consequence of the densest possible packing of the molecules within the crystal with the least possible repulsion.…”

Section: Introductionmentioning

confidence: 99%

Exciton properties of selected aromatic hydrocarbon systems

et al. 2013

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We have examined the singlet excitons in two representatives of acene-type (tetracene and pentacene) and phenacene-type (chrysene and picene) molecular crystals, respectively, using electron energy-loss spectroscopy at low temperatures. We show that the excitation spectra of the two hydrocarbon families significantly differ. Moreover, close inspection of the data indicates that there is an increasing importance of charge-transfer excitons at lowest excitation energy with increasing length of the molecules.

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Section: Introductionmentioning

confidence: 99%

Exciton properties of selected aromatic hydrocarbon systems

et al. 2013

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“…Substitutional doping of diamond with boron also induces a superconducting state, with a critical temperature in the range 4-10 K 4,5 . The most recent breakthroughs within the family of carbon-based materials are the discoveries of superconductivity in doped polycyclic aromatic hydrocarbons, namely picene 6 , phenanthrene 7 , coronene 8 , and dibenzopentacene 9 , with critical temperatures up to 33 K 9 .…”

Section: Introductionmentioning

confidence: 99%

Two-gap superconductivity in heavilyn-doped graphene:Ab initioMigdal-Eliashberg theory

Margine

Giustino

2014

Phys. Rev. B

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Graphene is the only member of the carbon family from zero-to three-dimensional materials for which superconductivity has not been observed yet. At this time, it is not clear whether the quest for superconducting graphene is hindered by technical challenges, or else by the fluctuation of the order parameter in two dimensions. In this area, ab initio calculations are useful to guide experimental efforts by narrowing down the search space. In this spirit, we investigate from first principles the possibility of inducing superconductivity in doped graphene using the fully anisotropic MigdalEliashberg theory powered by Wannier-Fourier interpolation. To address a best-case scenario, we consider both electron and hole doping at high carrier densities, so as to align the Fermi level to a van Hove singularity. In these conditions, we find superconducting gaps of s−wave symmetry, with a slight anisotropy induced by the trigonal warping, and, in the case of n-doped graphene, an unexpected two-gap structure reminiscent of MgB2. Our Migdal-Eliashberg calculations suggest that the observation of superconductivity at low temperature should be possible for n-doped graphene at carrier densities exceeding 10 15 cm −2 .

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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.…”

mentioning

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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confidence: 99%

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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Superconductivity at 5 K in alkali-metal-doped phenanthrene

Cited by 208 publications

References 32 publications

Exciton properties of selected aromatic hydrocarbon systems

Exciton properties of selected aromatic hydrocarbon systems

Two-gap superconductivity in heavilyn-doped graphene:Ab initioMigdal-Eliashberg theory

Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids

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