TY - JOUR
T1 - Thermal conductivity decomposition in two-dimensional materials
T2 - Application to graphene
AU - Fan, Zheyong
AU - Pereira, Luiz Felipe C
AU - Hirvonen, Petri
AU - Ervasti, Mikko M.
AU - Elder, Ken R.
AU - Donadio, Davide
AU - Ala-Nissilä, Tapio
AU - Harju, Ari
PY - 2017/4/19
Y1 - 2017/4/19
N2 - Two-dimensional materials have unusual phonon spectra due to the presence of flexural (out-of-plane) modes. Although molecular dynamics simulations have been extensively used to study heat transport in such materials, conventional formalisms treat the phonon dynamics isotropically. Here, we decompose the microscopic heat current in atomistic simulations into in-plane and out-of-plane components, corresponding to in-plane and out-of-plane phonon dynamics, respectively. This decomposition allows for direct computation of the corresponding thermal conductivity components in two-dimensional materials. We apply this decomposition to study heat transport in suspended graphene, using both equilibrium and nonequilibrium molecular dynamics simulations. We show that the flexural component is responsible for about two-thirds of the total thermal conductivity in unstrained graphene, and the acoustic flexural component is responsible for the logarithmic divergence of the conductivity when a sufficiently large tensile strain is applied.
AB - Two-dimensional materials have unusual phonon spectra due to the presence of flexural (out-of-plane) modes. Although molecular dynamics simulations have been extensively used to study heat transport in such materials, conventional formalisms treat the phonon dynamics isotropically. Here, we decompose the microscopic heat current in atomistic simulations into in-plane and out-of-plane components, corresponding to in-plane and out-of-plane phonon dynamics, respectively. This decomposition allows for direct computation of the corresponding thermal conductivity components in two-dimensional materials. We apply this decomposition to study heat transport in suspended graphene, using both equilibrium and nonequilibrium molecular dynamics simulations. We show that the flexural component is responsible for about two-thirds of the total thermal conductivity in unstrained graphene, and the acoustic flexural component is responsible for the logarithmic divergence of the conductivity when a sufficiently large tensile strain is applied.
UR - http://www.scopus.com/inward/record.url?scp=85017787403&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.95.144309
DO - 10.1103/PhysRevB.95.144309
M3 - Article
SN - 1098-0121
VL - 95
SP - 1
EP - 10
JO - Physical Review B
JF - Physical Review B
IS - 14
M1 - 144309
ER -