The rise of graphene
A.K. Geim and K.S. Novoselov Nature Materials, vol. 6, March 2007
Presented by Angela Intermite Journal Club presentation 18/10/2010
Overview • Definition of graphene • History of a material that should not exist • Experimental evidence • Electronic structure • Electronic qualities • Electronic transport • Optical properties • Anomalous Quantum Hall Effect in monolayer and bilayer graphene • The mystery of the missing pie
Angela Intermite
The rise of graphene, 18/10/2010
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Graphene: a rising star
0D fullerenes
1D nanotubes
3D graphite
Angela Intermite
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The material that should not exist
L.D. Landau
Until 2004…
R. E. Peierls Angela Intermite
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The bridge between theory and experimental evidence
Graphene
• metastable state but strong interatomic bonds
1 layer Boron Nitride
no thermal fluctuations • crumpling in the third dimension
½ layer BSCCO
gain in elastic energy
Angela Intermite The rise of graphene, 18/10/2010 6/16
Graphene electronic structure: semimetal
Semiconductor with direct gap
Graphene
Semiconductor with indirect gap
Semimetal
Angela Intermite
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Electronic qualities: quasiparticles and ballistic transistors
Ballistic transistor: free flowing electrons are forced around a wedge-shaped obstacle in one direction or another, corresponding to a logical 1 or 0.
Angela Intermite
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Electronic transport
• High electron mobility: 15.000 cm2 V-1 s-1 • Resistivity 10-6 cm < silver • Minimum conductivity on the order of 4e2/h
Angela Intermite The rise of graphene, 18/10/2010 9/16
References: 1. “The rise of graphene”, A.K. Geim and K.S. Novoselov, Nature materials, Vol. 6, March 2007 2. “ Room temperature quantum Hall Effect” K.S. Novoselov and al., Science, Vol. 315. no. 5817, p. 1379, March 2007 3. “The electronic properties of graphene”, A.H. Castro Neto et al., Rev of Mod Physics, vol. 81, Jan-March 2009 Angela Intermite The rise of graphene, 18/10/2010 15/16 Thank you for your attention Angela.Intermite@quasar-group.org