Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe...
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![Page 1: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/1.jpg)
ab initio calculation of pristine picene and potassium doped picene
Kotaro YamadaKusakabe laboratory
Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78 (2009) 113704 . R. Mitsuhashi et al.: Nature 464 (2010) 76 . G. Giovanetti et al.: Phys. Rev. B 83 (2011) 134508 .
![Page 2: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/2.jpg)
Contents• Introduction
• Paper’s reviews: Discovery of the superconductivity in K-doped picene
• Pristine picene and potassium doped picene
• ab initio calculation of picene
• Summary
• My work: LDA v.s. beyond LDA
![Page 3: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/3.jpg)
Superconducting power cable
Introduction•Why does Superconductivity have value to
study?
・Why am I studying about hydrocarbon superconductor?
To realize ecologicalsociety
Discovery of new mechanism
Study on hydrocarbon superconductor
Today’s normalPower cable
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What is picene?→C22H14
•picene has 5 benzene units with the shape of an arm chair .
From wikipedia
M/H
(10
–4 e
.m.u
. g–1
)
b 1.0
FC
0.0
–1.0
–2.0
–3.0
ZFC
–4.0 5 15 25
18 K
R. Mitsuhashi, et al.: Nature 464 (2010) 76.
K-doping creates superconductivity
T(K)
![Page 5: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/5.jpg)
The structure of pristine Picene
•Pristine picene has the herringbone structure.
Two dimensional electronic structure of pristine picene is fixed.Exp. & Theory agree!
T. Kosugi et al.:J.Phys.Soc.Jpn. 78 (2009) 113704.
R. Mitsuhashi, et al.: Nature 464 (2010) 76.
![Page 6: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/6.jpg)
Herringbone structure
The herringbone structure appears to balance local electric polarizations of molecules.
pentacene
hexabenzocoronene
picenepentacene
hexabenzocoronene
There are several crystals of hydrocarbons with the Herringbone structure.
picene
![Page 7: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/7.jpg)
A structure of potassium doped picene
G. Giovanetti et al.: Phys. Rev. B 83 (2011) 134508.
Tc=7K or 18K•Superconductor in experiment
•Structure by theory
However, crystal structure is unknown.This picture is theoretical image.
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Possible origin of superconductivity Superconductivity of K3-Picene may appear owing to•Electron-Phonon interaction
▫ Electrons are bounded by electron-phonon interaction, which forms the Cooper pairs.
•Electron-electron interaction▫ Electrons in a pair are repelled each other by
the repulsion. But, in an unconventional superconductor, the repulsion may induce pairing.
•Pair-Hopping Mechanism* for layered superconductor
* K. Kusakabe, J.Phys. Soc. Jpn 78, 114716(2009) The unconventional superconductor: 異方的超伝導などの非 BCS型超伝導を指す.
![Page 9: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/9.jpg)
ab initio calculation of piceneIn the density functional theory, we may apply,
⇒LDA(Local Density Approximation)
GRADIENT OF DENSITY is not used!
⇒GGA(Generalized Gradient Approximation) GRADIENT OF DENSITY is used! Both approximation are efficient with some accuracy.
![Page 10: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/10.jpg)
structure relax calculation
DFT+LDA(or )GGA “Quantum
espresso”
Input data
Out put
results・ Total force・ Total Energy・ Internal stress
Includes・ atomic position
Simultaneously out put
Initial condition
automatically
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What can we extract from output information?
•Total force meta stable state. →finding specific one of the stable state •Total Energy
•Internal stress
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Calculation results with GGA
Viewing from y direction
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summary•To investigate superconducting K-
doped picene, we determined K3-picene by the structural determination using GGA.
•Pristine and potassium-doped picene have the herringbone structure.
•Using ab initio method, it is able to calculate K3-picene’s structure in both atmoic and electronic-degrees of freedom.
![Page 14: Ab initio calculation of pristine picene and potassium doped picene Kotaro Yamada Kusakabe laboratory Reference: T. Kosugi et al.: J. Phys. Soc. Jpn. 78.](https://reader036.fdocument.pub/reader036/viewer/2022062409/56649cb75503460f9497d861/html5/thumbnails/14.jpg)
Future work• I calculate K3-Picene using quantum espresso with LDA
and GGA .
• Decide which approximation tells a result close to the experimental result.
• Calculate the band structure.
• Identify the Fermi surface.
• Consider similarity of doped picene with other hydro-carbon superconductors.
• Not only calculation structure with quantum espresso, but Tc also needs to be evaluated