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

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

151 Downloads (Pure)

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

Access to Document

10.1134/S0021364018090023

Accepted ManuscriptAccepted author manuscript, 170 KB

1 Article
1 Letter
1 Doctoral Thesis

Charge Density Waves in Graphite: Towards the Magnetic Ultraquantum Limit
Arnold, F., Isidori, A., Kampert, E., Yager, B., Eschrig, M. & Saunders, J., 26 Sept 2017, In: Physical Review Letters. 119, 13, p. 1-6 6 p., 136601.
Research output: Contribution to journal › Letter › peer-review

Open Access
File

338 Downloads (Pure)
Experimental Study of Strongly Correlated Fermion Systems under Extreme Conditions: Two-Dimensional 3He at Ultra-Low Temperatures and Graphite in the Magnetic Ultra-Quantum Limit
Arnold, F., 2015, (Unpublished) 262 p.
Research output: Thesis › Doctoral Thesis

File
Spear-anvil point-contact spectroscopy in pulsed magnetic fields
Arnold, F., Yager, B., Kampert, E., Putzke, C., Nyéki, J. & Saunders, J., 30 Nov 2013, In: Review of Scientific Instruments. 84, 11, 5 p., 113901.
Research output: Contribution to journal › Article › peer-review

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

Cite this

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title = "Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy",

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.",

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AU - Arnold, Frank

AU - Nyeki, Jan

AU - Saunders, John

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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 critical superconducting 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 critical superconducting temperature of 14K.

KW - Graphite

KW - Graphene

KW - Superconductivity

KW - Point-Contact Spectroscopy

U2 - 10.1134/S0021364018090023

DO - 10.1134/S0021364018090023

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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

Abstract

Keywords

Access to Document

Research output

Charge Density Waves in Graphite: Towards the Magnetic Ultraquantum Limit

Experimental Study of Strongly Correlated Fermion Systems under Extreme Conditions: Two-Dimensional 3He at Ultra-Low Temperatures and Graphite in the Magnetic Ultra-Quantum Limit

Spear-anvil point-contact spectroscopy in pulsed magnetic fields

Projects

Quantum Phase Transitions and Quantum Criticality in Helium Films

Cite this