Structure and phonon density of states in nanoclusters: Molecular dynamics study for Al

1997 ◽  
Vol 15 (5) ◽  
pp. 1610 ◽  
Author(s):  
W. Schommers
Keyword(s):  
Molecular Dynamics ◽  
Density Of States ◽  
Phonon Density ◽  
Phonon Density Of States

NONLINEAR DYNAMIC EXCITATIONS AND PHONONS IN NANOSYSTEMS

1994 ◽  
Vol 08 (02) ◽  
pp. 103-111
Author(s):  
W. SCHOMMERS ◽  
H. KLANN ◽  
C. POLITIS ◽  
P. PAPANIKOLAOU ◽  
N. ATHANASIOU
Keyword(s):  
Molecular Dynamics ◽  
Density Of States ◽  
Interaction Potential ◽  
Nonlinear Dynamic ◽  
Phonon Density ◽  
Phonon Density Of States ◽  
Precise Knowledge ◽  
Cluster Properties ◽  
Dynamic Excitations ◽  
Reliable Interaction

The phonon density of states for nanoclusters has been studied theoretically using molecular dynamics; in this way, anharmonic effects could be fully considered. Comparisons are made with results obtained from bulk calculations. The cluster properties have been studied for several particle numbers and temperatures. It turned out that the properties of clusters are sensitive to small variations in the interactions between the particles. Therefore, in the calculation of cluster properties, the precise knowledge of the interaction is necessary. In our study, we have chosen krypton nanosystems because for this substance, a reliable interaction potential is available. First estimations have also been performed for metal (Al, Pb) systems.

Thermal Rectification in Bi-Layered Nanofilm by Molecular Dynamics

2009 ◽  
Author(s):  
Shuai-Chuang Wang ◽  
Xin-Gang Liang
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Heat Flux ◽  
Density Of States ◽  
Atomic Mass ◽  
Interfacial Thermal Resistance ◽  
Phonon Density ◽  
Total Thickness ◽  
Phonon Density Of States ◽  
Thermal Rectification

A thermal rectifier has such nature that its thermal conductance or thermal conductivity has different values with reversed heat flux direction. This work investigates the rectification of the cross-plane thermal conductivity and interfacial thermal resistance of nanoscale bi-layered films using the nonequilibrium molecular dynamics (NEMD) method. The effects of the thickness of the single layer with the total thickness constant, the ratio of the atomic mass and temperature difference in the two ends on the thermal rectification are all considered. The results of the simulations show that the thermal conductivity and the interfacial thermal resistance are different for the heat flux with opposite directions. For the composite film with two layers of the same thicknesses, the thermal conductivity is larger when the heat flux direction is from the light layer to the heavy one. The difference becomes larger when the ratio of the atomic mass in the two layers increases. Increasing the heat flux makes the rectification of thermal conductivity larger, which means that the rectification is dependent on the temperature. For the composite film with fixed total thickness, the rectification becomes smaller when the thickness of the light layer increases. When the light layer is thick enough, the rectification is found reversed, which means that the thermal conductivity is larger with the heat flux direction from the heavy layer to the light one. The phonon density of states is also calculated to explain the phenomenon, and it is found that the overlap of the phonon density of states for the two layers is almost same even if the rectification of the thermal conductivity is reversed.

Thermal Rectification Characteristics of Graphene Nanoribbons of Asymmetric Geometries

MRS Advances ◽  
2016 ◽  
Vol 2 (1) ◽  
pp. 15-20
Author(s):  
T. Iwata ◽  
K. Shintani
Keyword(s):  
Molecular Dynamics ◽  
Heat Transport ◽  
Density Of States ◽  
Graphene Nanoribbons ◽  
Longitudinal Direction ◽  
Nonequilibrium Molecular Dynamics ◽  
Phonon Density ◽  
Rectification Ratio ◽  
Phonon Density Of States ◽  
Thermal Rectification

ABSTRACTThe rectification of heat in graphene nanoribbons (GNRs) of asymmetric geometries is investigated by means of nonequilibrium molecular dynamics (NEMD). Two kinds of geometries of GNRs are addressed; a trapezoidal or T-shaped step is inserted halfway through a GNR in its longitudinal direction. The thermal conductivities (TCs) of the GNRs in the two longitudinal directions, forward and backward, are calculated making their width and temperature change. It is revealed that the thermal rectification ratio (TRR) of T-shaped GNRs are larger than those of trapezoidal GNRs and that the characteristics of heat transport in such asymmetric GNRs can be understood by considering the local phonon density of states (DOSs).

The Phonon Densities of States of AlN and ZrN

1995 ◽  
Vol 395 ◽  
Author(s):  
C.-K. Loong
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Density Of States ◽  
Neutron Spectroscopy ◽  
Phonon Density ◽  
Phonon Density Of States ◽  
Phonon Spectra ◽  
Densities Of States ◽  
The One ◽  
Dynamics Simulations

ABSTRACTPhonons are thought to play a crucial role in the high thermal conductivity of AIN and ZrN. Using time-of-flight neutron spectroscopy, we have measured the phonon spectra of A1N and ZrN up to 300 meV (2400 cm−1). The one-phonon density of states (DOS) of AIN exhibits relatively sharp bands at about 33, 63, 83 and 91 meV. In addition, distinct multiple-phonon excitations were observed at ∼173 and 255 meV. The phonon DOS of ZrN displays similar features with the corresponding phonon energies shifted toward lower energies. The measured DOS of AIN is compared with results of molecular-dynamics simulations.

The solids phonon density of states reconstruction from the heat-type experiments: the computation resources

1998 ◽  
Vol 3 (0) ◽  
pp. 135-138
Author(s):  
В. М. Різак ◽  
І. М. Різак ◽  
І. П. Коссей ◽  
В. В. Маслюк
Keyword(s):  
Density Of States ◽  
Phonon Density ◽  
Phonon Density Of States

scholarly journals Phonon density of states in Fe/Cr(001) superlattices and Tb–Fe thin-film alloys

1999 ◽  
Vol 198-199 ◽  
pp. 590-592 ◽  
Author(s):  
W. Sturhahn ◽  
R. Roehlsberger ◽  
E.E. Alp ◽  
T. Ruckert ◽  
H. Schrör ◽  
...  
Keyword(s):  
Thin Film ◽  
Density Of States ◽  
Phonon Density ◽  
Phonon Density Of States
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