Evidence for metallic states in potassium-intercalated picene film on graphite

Okazaki, Hiroyuki; Jabuchi, Taihei; Wakita, Takanori; Kato, Takashi; Muraoka, Yuji; Yokoya, Takayoshi

doi:10.1103/physrevb.88.245414

Cited by 18 publications

(28 citation statements)

References 40 publications

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“…See, for example, the observation of orbital hybridization between picene (C 2p) and potassium (K 4s) near the Fermi energy obtained by Yamane and Kosugi [41] using soft x-ray spectroscopies or the zero resistivity measurement by Teranishi et al [7]. Moreover, metallic states in K-intercalated picene films on graphite have been observed very recently [42].…”

Section: Discussionmentioning

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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Section: Discussionmentioning

confidence: 99%

Role of potassium orbitals in the metallic behavior ofK3picene

et al. 2014

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“…To date, several basic studies of the electronic structure of these materials have so far been conducted using film samples by means of photoemission spectroscopy, [8][9][10][11][12] electron energyloss spectroscopy, 13,14 and X-ray emission spectroscopy. 15 However, these various groups have reported contradictory results that indicate differing pictures of the electronic ground states, from insulating 9-11 to metallic one.…”

Section: Introductionmentioning

confidence: 99%

“…15 However, these various groups have reported contradictory results that indicate differing pictures of the electronic ground states, from insulating 9-11 to metallic one. 8,12 These discrepancies may originate from variations in the molecular arrangement within the films, having been prepared on different substrates with different thicknesses. Theoretical reports on these materials have also reached various conclusions about the normal electronic state, again ranging from insulating 11 to metallic state, [16][17][18][19][20][21][22][23][24] which also depends strongly on the crystal structure.…”

Section: Introductionmentioning

confidence: 99%

Well-ordered monolayers of alkali-doped coronene and picene: Molecular arrangements and electronic structures

Yano

Endo

Hasegawa

et al. 2014

The Journal of Chemical Physics

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Adsorptions of alkali metals (such as K and Li) on monolayers of coronene and picene realize the formation of ordered phases, which serve as well-defined model systems for metal-intercalated aromatic superconductors. Upon alkali-doping of the monolayers of coronene and picene, scanning tunneling microscopy and X-ray absorption spectroscopy revealed the rearrangement of the entire molecular layer. The K-induced reconstruction of both monolayers resulted in the formation of a structure with a herringbone-like arrangement of molecules, suggesting the intercalation of alkali metals between molecular planes. Upon reconstruction, a shift in both the vacuum level and core levels of coronene was observed as a result of a charge transfer from alkali metals to coronene. In addition, a new density of states near the Fermi level was formed in both the doped coronene and the doped picene monolayers. This characteristic electronic feature of the ordered monolayer has been also reported in the multilayer picene films, ensuring that the present monolayer can model the properties of the metal-intercalated aromatic hydrocarbons. It is suggested that the electronic structure near the Fermi level is sensitive to the molecular arrangement, and that both the strict control and determinations of the molecular structure in the doped phase should be important for the determination of the electronic structure of these materials.

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“…The absence of metallicity has been observed in K-doped picene in [6], [7], and [12]. However, Okazaki et al [17] recently reported metallic behavior in K-doped picene film based on the high-resolution photoemission spectroscopy measurements. Comparing previous studies, we found that the existence or absence of the metallic behavior is also related to the crystal structural character.…”

Section: Resultsmentioning

confidence: 92%

Antiferromagnetism in Potassium-Doped Polycyclic Aromatic Hydrocarbons

2014

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First-principles density functional calculations are performed to investigate the magnetic characteristics in K-doped polycyclic aromatic hydrocarbons (PAHs) including phenanthrene, picene, 1,2:5,6-dibenzanthracene, 7-phenacene, and 1,2;8,9-dibenzopentacene. With the help of lowest energy crystal structures, the calculated total energies indicate that all five K-doped PAHs are stabilized in an antiferromagnetic ground state, with antiparallel spins between two molecular layers. The magnetic moment in these K-doped PAHs is increased with the increase of benzene rings number, while it is not sensitive to the arrangement of benzene rings. The enhancement of the magnetic moment is caused by a stronger spin splitting near the Fermi level and an increase of magnetic C atoms induced by K atoms with the increase of molecular size. Our results also indicate that the magnetism strongly depends on the crystal structure.

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Evidence for metallic states in potassium-intercalated picene film on graphite

Cited by 18 publications

References 40 publications

Role of potassium orbitals in the metallic behavior ofK3picene

Role of potassium orbitals in the metallic behavior ofK3picene

Well-ordered monolayers of alkali-doped coronene and picene: Molecular arrangements and electronic structures

Antiferromagnetism in Potassium-Doped Polycyclic Aromatic Hydrocarbons

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