Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy

Frank Arnold; Jan Nyeki; John Saunders

doi:10.1134/S0021364018090023

Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy

Frank Arnold, Jan Nyeki, John Saunders

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Abstract

In this letter we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of microcrystalline graphite. Magnetic field dependent point-contact spectroscopy was carried out at a temperature of 1.8K using an etched aluminium tip. At zero field a gap structure in the differential conductance is observed, showing a gap of Δ = 4.2meV. On applying magnetic fields of up to 500mT, this gap gradually closes, following the theoretical prediction by Ginzburg and Landau for a fully flux-penetrated superconductor. By applying BCS-theory, we infer a critical
superconducting temperature of 14K.

Original language	English
Pages (from-to)	577-578
Number of pages	2
Journal	JETP LETTERS
Volume	107
Issue number	9
DOIs	https://doi.org/10.1134/S0021364018090023
Publication status	E-pub ahead of print - 2 May 2018

Keywords

Graphite
Graphene
Superconductivity
Point-Contact Spectroscopy

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10.1134/S0021364018090023

Accepted ManuscriptAccepted author manuscript, 170 KB

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Quantum Phase Transitions and Quantum Criticality in Helium Films
Saunders, J., Casey, A., Nyeki, J., Lusher, C., Cowan, B., Yager, B., Kent, K. & Arnold, F.
Eng & Phys Sci Res Council EPSRC
1/06/10 → 1/11/13
Project: Research

Cite this

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abstract = "In this letter we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of microcrystalline graphite. Magnetic field dependent point-contact spectroscopy was carried out at a temperature of 1.8K using an etched aluminium tip. At zero field a gap structure in the differential conductance is observed, showing a gap of Δ = 4.2meV. On applying magnetic fields of up to 500mT, this gap gradually closes, following the theoretical prediction by Ginzburg and Landau for a fully flux-penetrated superconductor. By applying BCS-theory, we infer a criticalsuperconducting temperature of 14K.",

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T1 - Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy

AU - Arnold, Frank

AU - Nyeki, Jan

AU - Saunders, John

PY - 2018/5/2

Y1 - 2018/5/2

N2 - In this letter we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of microcrystalline graphite. Magnetic field dependent point-contact spectroscopy was carried out at a temperature of 1.8K using an etched aluminium tip. At zero field a gap structure in the differential conductance is observed, showing a gap of Δ = 4.2meV. On applying magnetic fields of up to 500mT, this gap gradually closes, following the theoretical prediction by Ginzburg and Landau for a fully flux-penetrated superconductor. By applying BCS-theory, we infer a criticalsuperconducting temperature of 14K.

AB - In this letter we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of microcrystalline graphite. Magnetic field dependent point-contact spectroscopy was carried out at a temperature of 1.8K using an etched aluminium tip. At zero field a gap structure in the differential conductance is observed, showing a gap of Δ = 4.2meV. On applying magnetic fields of up to 500mT, this gap gradually closes, following the theoretical prediction by Ginzburg and Landau for a fully flux-penetrated superconductor. By applying BCS-theory, we infer a criticalsuperconducting temperature of 14K.

KW - Graphite

KW - Graphene

KW - Superconductivity

KW - Point-Contact Spectroscopy

U2 - 10.1134/S0021364018090023

DO - 10.1134/S0021364018090023

M3 - Letter

SN - 0021-3640

VL - 107

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EP - 578

JO - JETP LETTERS

JF - JETP LETTERS

IS - 9

ER -

Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy

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Keywords

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Projects

Quantum Phase Transitions and Quantum Criticality in Helium Films

Cite this