Superconducting Calcium-Intercalated Bilayer Graphene

Satoru Ichinokura; Katsuaki Sugawara; Akari Takayama; Takashi Takahashi; Shuji Hasegawa

doi:10.1021/acsnano.5b07848

Superconducting Calcium-Intercalated Bilayer Graphene

Satoru Ichinokura, Katsuaki Sugawara, Akari Takayama, Takashi Takahashi, Shuji Hasegawa

SCI - Physics

The University of Tokyo

Research output: Contribution to journal › Article › peer-review

189 Citations (Scopus)

Abstract

We report the direct evidence for superconductivity in Ca-intercalated bilayer graphene C₆CaC₆, which is regarded as the thinnest limit of Ca-intercalated graphite. We performed the electrical transport measurements with the in situ 4-point-probe method in ultrahigh vacuum under zero-or nonzero-magnetic field for pristine bilayer graphene, Li-intercalated bilayer graphene (C₆LiC₆) and C₆CaC₆ fabricated on SiC substrate. We observed that the zero-resistance state occurs in C₆CaC₆ with the onset temperature (T_c^onset) of 4 K, while the T_c^onset is gradually decreased upon applying the magnetic field. This directly proves the superconductivity origin of the zero resistance in C₆CaC₆. On the other hand, both pristine bilayer graphene and C₆LiC₆ exhibit nonsuperconducting behavior, suggesting the importance of intercalated atoms and its species to drive the superconductivity.

Original language	English
Pages (from-to)	2761-2765
Number of pages	5
Journal	ACS Nano
Volume	10
Issue number	2
DOIs	https://doi.org/10.1021/acsnano.5b07848
Publication status	Published - 2016 Feb 23

Keywords

carbon
electrical transport
graphene
graphite-intercalation-compound
semiconductor surface
superconductivity
ultrahigh vacuum

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10.1021/acsnano.5b07848

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title = "Superconducting Calcium-Intercalated Bilayer Graphene",

abstract = "We report the direct evidence for superconductivity in Ca-intercalated bilayer graphene C6CaC6, which is regarded as the thinnest limit of Ca-intercalated graphite. We performed the electrical transport measurements with the in situ 4-point-probe method in ultrahigh vacuum under zero-or nonzero-magnetic field for pristine bilayer graphene, Li-intercalated bilayer graphene (C6LiC6) and C6CaC6 fabricated on SiC substrate. We observed that the zero-resistance state occurs in C6CaC6 with the onset temperature (Tconset) of 4 K, while the Tconset is gradually decreased upon applying the magnetic field. This directly proves the superconductivity origin of the zero resistance in C6CaC6. On the other hand, both pristine bilayer graphene and C6LiC6 exhibit nonsuperconducting behavior, suggesting the importance of intercalated atoms and its species to drive the superconductivity.",

keywords = "carbon, electrical transport, graphene, graphite-intercalation-compound, semiconductor surface, superconductivity, ultrahigh vacuum",

author = "Satoru Ichinokura and Katsuaki Sugawara and Akari Takayama and Takashi Takahashi and Shuji Hasegawa",

note = "Funding Information: We thank R. Akiyama and Y. Endo at University of Tokyo, and K. Suzuki and T. Sato at Tohoku University for their useful discussions. This work was supported by the JSPS (KAKENHI 15H02105, 25246025, 22246006) and the MEXT (Grant-in-Aid for Scientific Research on Innovative Areas {"}Science of Atomic Layers{"} 25107003 and {"}Molecular Architectonics{"} 25110010), and Program for Key Interdisciplinary Research. S.I. thanks JSPS for financial support. Publisher Copyright: {\textcopyright} 2016 American Chemical Society.",

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T1 - Superconducting Calcium-Intercalated Bilayer Graphene

AU - Ichinokura, Satoru

AU - Sugawara, Katsuaki

AU - Takayama, Akari

AU - Takahashi, Takashi

AU - Hasegawa, Shuji

N1 - Funding Information: We thank R. Akiyama and Y. Endo at University of Tokyo, and K. Suzuki and T. Sato at Tohoku University for their useful discussions. This work was supported by the JSPS (KAKENHI 15H02105, 25246025, 22246006) and the MEXT (Grant-in-Aid for Scientific Research on Innovative Areas "Science of Atomic Layers" 25107003 and "Molecular Architectonics" 25110010), and Program for Key Interdisciplinary Research. S.I. thanks JSPS for financial support. Publisher Copyright: © 2016 American Chemical Society.

PY - 2016/2/23

Y1 - 2016/2/23

N2 - We report the direct evidence for superconductivity in Ca-intercalated bilayer graphene C6CaC6, which is regarded as the thinnest limit of Ca-intercalated graphite. We performed the electrical transport measurements with the in situ 4-point-probe method in ultrahigh vacuum under zero-or nonzero-magnetic field for pristine bilayer graphene, Li-intercalated bilayer graphene (C6LiC6) and C6CaC6 fabricated on SiC substrate. We observed that the zero-resistance state occurs in C6CaC6 with the onset temperature (Tconset) of 4 K, while the Tconset is gradually decreased upon applying the magnetic field. This directly proves the superconductivity origin of the zero resistance in C6CaC6. On the other hand, both pristine bilayer graphene and C6LiC6 exhibit nonsuperconducting behavior, suggesting the importance of intercalated atoms and its species to drive the superconductivity.

AB - We report the direct evidence for superconductivity in Ca-intercalated bilayer graphene C6CaC6, which is regarded as the thinnest limit of Ca-intercalated graphite. We performed the electrical transport measurements with the in situ 4-point-probe method in ultrahigh vacuum under zero-or nonzero-magnetic field for pristine bilayer graphene, Li-intercalated bilayer graphene (C6LiC6) and C6CaC6 fabricated on SiC substrate. We observed that the zero-resistance state occurs in C6CaC6 with the onset temperature (Tconset) of 4 K, while the Tconset is gradually decreased upon applying the magnetic field. This directly proves the superconductivity origin of the zero resistance in C6CaC6. On the other hand, both pristine bilayer graphene and C6LiC6 exhibit nonsuperconducting behavior, suggesting the importance of intercalated atoms and its species to drive the superconductivity.

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Superconducting Calcium-Intercalated Bilayer Graphene

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