ABSTRACT
Graphene, a single-layer hexagonal lattice of carbon atoms, has
emerged recently as a fascinating system for fundamental studies
in condensed matter physics, as well as a promising candidate
material for future applications in carbon-based nanoelectronics
and molecular devices [1, 2]. Since the honeycomb crystal structure
of graphene consists of two nonequivalent sublattices, graphene has
a unique band structure for the itinerant π -electrons near the Fermi
energy. In particular, as we have seen in Chapter 2, the motion of
electrons in graphene near the Fermi energy is well described by
the massless Dirac equation. The valence and conduction bands
conically touch at two nonequivalent Dirac points, which are called
the K and K ′ points. Because of the peculiar linear energy spectrum, graphene provides an environment for highly unconventional and
fascinating two-dimensional (2D) electronic properties [3-5] such
as the half-integer quantum Hall effect [6, 7], the absence of
backward scattering [4, 8, 9], Klein tunneling [10], and the π -
phase shift of Shubnikov-de Haas oscillations [11]. Owing to its high
electronic mobility [12] and thermal conductivity [13], graphene is
recognized as one of the key materials for realizing next-generation
electronic devices.
