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Extended van Hove singularity and superconducting instability in doped graphene
J L McChesney1, Aaron Bostwick, Taisuke Ohta
1Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
Physical Review Letters
|May 21, 2010
Summary
Doping graphene warps its Fermi surface, creating an extended van Hove singularity. This singularity enhances superconductivity over magnetic instability, enabling pairing 1 meV below the Fermi energy.
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- Single-layer graphene exhibits unique electronic properties.
- Doping significantly alters graphene's electronic structure and interactions.
Purpose of the Study:
- To investigate the impact of doping on graphene's Fermi surface.
- To analyze the interplay between magnetic and superconducting instabilities in doped graphene.
Main Methods:
- Angle-resolved photoemission spectroscopy (ARPES) was employed.
- Theoretical calculations of ground state properties were performed.
Main Results:
- Many-body interactions were found to significantly warp the Fermi surface.
- An extended van Hove singularity (EVHS) was observed at the graphene M point.
- Superconductivity was identified as the dominant instability, enhanced by Fermi line modulation.
Conclusions:
- The observed EVHS in doped graphene promotes superconductivity.
- A pairing instability energy scale of up to 1 meV was determined.
- The findings offer insights into novel electronic phases in 2D materials.
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