Environmental Engineering Reference
In-Depth Information
Chapter 3
Thermal Conduction of Graphene
Yong Xu
a,b
and Wenhui Duan
a
a
Department of Physics, Tsinghua University, Beijing 100084, China
b
Theory Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft,
Berlin 14195, Germany
dwh@phys.tsinghua.edu.cn
3.1 Basic Concepts of Quantum Thermal Transport
3.1.1
Thermal-Transport Carriers
In physics, transport concerns the movements of physical entities
(e.g., mass, charge, momentum, and energy) in the presence of
inhomogeneities. Thermal transport, as one type of transport
phenomena, is the exchange of energy (or heat) as a result of the
temperature gradient. Electrons and phonons are major carriers
of thermal transport in solids. In semiconductors and insulators,
phonons, which are the collective excitation of lattice vibrations,
are the main contributor to thermal transport. While in metals, a
significant part of thermal conductance comes from electrons. A
simple relation between the electronic contribution to the thermal
conductivity (
κ
e
) and the electrical conductivity (
σ
e
)existsfor
metals.AsrevealedbytheWiedemann-Franzlaw,theratiobetween
