Absence of Metallicity in K-doped Picene: Importance of Electronic Correlations

Ruff, A.; Sing, M.; Claessen, R.; Lee, Hunpyo; Tomić, Milan; Jeschke, Harald O.; Valentí, Roser

doi:10.1103/physrevlett.110.216403

Cited by 58 publications

(76 citation statements)

References 44 publications

(45 reference statements)

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“…In this context both many-body effects and electron-phonon interactions would be important [9,[14][15][16][37][38][39][40]. Finally, let us remind one that after the seminal work by Mitsuhashi et al [1] showing the existence of superconducting phases for potassium-intercalated picene, additional experimental evidence points to a metallic behavior of K 3 picene.…”

Section: Discussionmentioning

confidence: 99%

“…3 of Ref. [14]). Notice that our interaction model is similar to theirs (although we are coupling K and picene bands and our U value is sensibly larger), and therefore, our quarter-filled two-band model produces a spectral function that resembles the one shown at the top of the mentioned figure ( Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Parallel to the experimental work there have been several theoretical calculations of the electronic structure of potassium-intercalated picene [8][9][10][11][12][13][14][15]. According to x-raydiffraction experiments, potassium enters into the intralayer herringbone arrangement of picene molecules.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Role of potassium orbitals in the metallic behavior ofK3picene

et al. 2014

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“…The change in the computed geometry of picene in K2Picene compared to solid picene is consistent with the occupation of the LUMO orbital when forming the dianion (Supplementary Figure 28). Density functional plus dynamical mean field theory (DFT+DMFT) calculations on KxPicene 39 suggest the opening of a Mott gap by electron correlation in both LUMO and LUMO+1 bands in a multi-orbital correlated model, 40 which is required to explain the insulating behaviour of Cs2Phenanthrene, 32 and such correlation effects, which are not captured at the level of theory used here, may also contribute to the gap in the picene dianion solid. Raman spectroscopy does identify differences in the electronic behaviour of the K2Pentacene and K2Picene: high-frequency Raman modes display significant broadening in K2Picene, implying electron-phonon coupling, which is not observed in K2Pentacene (see Supplementary Section 4).…”

Section: Electronic Structurementioning

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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“…1 and Table I). Interacting electron theories that have been constructed for the doped acenes and phenacenes [20][21][22] , however, still fail to explain the two crucial experimental observations completely. Taking the combined effects of the Hubbard U and nonzero ∆ L,L+1 into consideration, reference 20 has concluded that K 3 picene in the normal state is a Mott-Hubbard semiconductor, with a completely filled L-band and a 1 2 -filled L+1-band.…”

Section: Introductionmentioning

confidence: 99%

Theory of metal-intercalated phenacenes: Why molecular valence 3 is special

Dutta

Mazumdar

2014

Phys. Rev. B

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We develop a correlated-electron minimal model for the normal state of charged phenanthrene ions in the solid state, within the reduced space of the two lowest antibonding molecular orbitals of phenanthrene. Our model is general and can be easily extended to study the normal states of other polycyclic aromatic hydrocarbon superconductors. The main difference between our approach and previous correlated-electron theories of phenacenes is that our calculations are exact within the reduced basis space, albeit for finite clusters. The enhanced exchange of electron populations between these molecular orbitals, driven by Coulomb interactions over and above the bandwidth effects, gives a theoretical description of the phenanthrene trianions that is very different from previous predictions. Exact many-body finite cluster calculations show that while the systems with molecular charges of −1 and −2 are one-and two-band Mott-Hubbard semiconductors, respectively, molecular charge −3 gives two nearly 3 4 -filled bands, rather than a completely filled lower band and a 1 2 -filled upper band. The carrier density per active molecular orbital is thus nearly the same in the normal state of the superconducting aromatics and organic charge-transfer solids, and may be the key to understanding unconventional superconductivity in these molecular superconductors.

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Absence of Metallicity in K-doped Picene: Importance of Electronic Correlations

Cited by 58 publications

References 44 publications

Role of potassium orbitals in the metallic behavior ofK3picene

Role of potassium orbitals in the metallic behavior ofK3picene

Redox-controlled potassium intercalation into two polyaromatic hydrocarbon solids

Theory of metal-intercalated phenacenes: Why molecular valence 3 is special

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