  The coherent oscillations of mobile charge carriers near the surface of good
conductors-surface plasmons-are been exploited in many applications in
information technologies, clean energy, high-density data storage,
photovoltaics, chemistry, biology, medicine and security. Light can be coupled
to surface plasmons and trapped near the interface between a metal and an
adjacent material. This leads to the nanoscale confinement of light, impossible
by any other means, and a related electromagnetic field enhancement.
Microscopic electron dynamic effects associated with surface plasmons are
capable of significantly influencing physical and chemical processes near a
conductor surface, not only as a result of the high electric fields, but also
via the excitation of energetic charge carriers: holes below Fermi level or
electrons above it. When remaining inside plasmonic media, these so-called hot
carriers result in nonlinear, Kerr-type, optical effects important for
controlling light with light. They can also transfer into the surroundings of
the nanostructures, resulting in photocurrent, or they can interact with
adjacent molecules and materials, inducing photochemical transformations.
Understanding the dynamics of hot carriers and related effects in plasmonic
nanostructures is essential for the development of ultrafast detectors and
nonlinear optical components, broadband photocatalysis, enhanced nanoscale
optoelectronic devices, nanoscale and ultrafast temperature control, and other
technologies of tomorrow. This review will discuss the basics of
plasmonically-engendered hot electrons, theoretical descriptions and
experimental methods to study them, and describe prototypical processes and
examples of the most promising applications of hot-electron processes at the
metal interfaces.
