First direct observation of Dirac fermions in graphite

By Shuyun Zhou, G. Gweon, J. Graf, A. Fedorov, C. Spataru, R. D. Diehl, Y. Kopelevich, D.-H. Lee, S. G. Louie, A. Lanzara. 2006

427 citations recorded by the source corpus.

Originating from relativistic quantum field theory, Dirac fermions have been invoked recently to explain various peculiar phenomena in condensed-matter physics, including the novel quantum Hall effect in graphene1,2, the magnetic-field-driven metal–insulator-like transition in graphite3,4, superfluidity in 3He (ref. 5) and the exotic pseudogap phase of high-temperature superconductors6,7. Despite their proposed key role in those systems, direct experimental evidence of Dirac fermions has been limited. Here, we report the first direct observation of relativistic Dirac fermions with linear dispersion near the Brillouin zone (BZ) corner H, which coexist with quasiparticles that have a parabolic dispersion near another BZ corner K. In addition, we also report a large electron pocket that we attribute to defect-induced localized states. Thus, graphite presents a system in which massless Dirac fermions, quasiparticles with finite effective mass and defect states all contribute to the low-energy electronic dynamics.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/c1f3fbc546135b877732ac742286c18ac740a7e6

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

In Materials Chemistry

Citations in the corpus

Angle-resolved photoemission studies of quantum materials (2020, neutral): “32(c)(d)) (Ohta et al., 2007; Zhou et al., 2006b).”
Graphene versus MoS2: A short review (2014, background): “The velocity of this Dirac fermion is at 1/300 the speed of light [165–167].”
Substrate-induced bandgap opening in epitaxial graphene. (2007, methodology): “The layer dependence of both quantities suggests that, beyond 5 layers, epitaxial graphene behaves as bulk graphite [18].”
Electronic properties of graphene in a strong magnetic field (2010, background): “…linearised version (40) in each valley for undeformed graphene. observe the effect, e.g. in angle-resolved photoemission spectroscopy (ARPES) measurements (Damascelli, 2004) that have been successfully applied to epitaxial graphene (Bostwick et al., 2007) and graphitic samples (Zhou et al., 2006).”
Production, properties and potential of graphene (2010, methodology): “Adapted with permission from (c) [23], copyright 2008 American Chemical Society; (d) [27], MacMillan Publishers Ltd: Nature Physics, copyright (2006); (e) [41], copyright 2007 American Chemical Society; (f) [42], copyright 2007 American Chemical Society;”
Observation of electron–hole puddles in graphene using a scanning single-electron transistor (2007, background): “The kinetic energy of Dirac particles in graphene increases linearly with momentum [1,15,16].”