Not very meaningful. Even room temperature is very questionable. For
temperature far below the Debye temperature, MD results are usually not
quantitatively correct (they can "happen" to be correct, if some opposite
quantum effects are cancelling each other). This paper compared classical
and quantum results using BTE:
Ultrahigh yet convergent thermal conductivity of carbon nanotubes from
comprehensive atomistic modeling
You can see how large the difference is!!!
On Fri, Apr 30, 2021 at 2:48 PM "소순성" <soonsung2001@xxxxxxxxxx> wrote:
Dear Zheyong Fan.
Thank you for direct advice!
Then, I wonder it is meaningful to calculate thermal conductivities for
graphene nano ribbon at low temperature (under 300K such as 40K, 100K, ...)
with MD method.
--------- Original Mail ---------Sender : Bruce Fan <brucenju@xxxxxxxxx>
Recipient : <gpumd@xxxxxxxxxxxxx>
Received Date : 2021/Apr/30(Fri) 14:03:55
Subject : [gpumd] Re: Quantum correction to thermal conductivity
Both papers are wrong. Forget about them. If you can solve the quantum
correction problem for graphene and alike, you can submit your paper to PRL
"소순성" <soonsung2001@xxxxxxxxxx> 于 2021年4月30日周五 04:55写道：
Thank you for Nice GPUMD program and I have question today.
When we deal with thermal conductivity of graphene at temperature below
the debye temperature,
it is reported in many papers that the thermal conductivity should be
treated with quantum-correction.
So I saw there are generally two methods that
1. from the paper1: Equilibrium Molecular Dynamics (MD) Simulation Study
of Thermal Conductivity of Graphene Nanoribbon: A Comparative Study on MD
Potentials (Electronics 2015, 4, 1109-1124)
which said that it can be calculated with thermal conductivity of MD
(k_md) multiplied by d(Tmd)/d(Tq), following the equation13 in the paper.
2. from the paper2: Lateral and flexural thermal transport in
stanene/2D-SiC van der Waals heterostructure, (2020 Nanotechnology 2020 31
which said that it can be calculated from Cv (specific heat) which can be
obtained with integration of phonon density of states.
As I got the phonon DOS at 300K and followed second method, Cvx=Cvy=0.18
and I obtained quantum-corrected thermal conducivity of
k_in-plane=1000*Cvy=180, k_flexural= 2000*Cvz=1000 (W/mK)
so that ktot=k_in-plane+k_flexural=1180 (W/mK)
However, this value is much lower than that in paper1, which shows little
difference after quantum-correction at 300K.
How can this problem be solved?