Assessment of the Holland model for silicon phonon-phonon relaxation times using lattice dynamics calculations

2013 ◽  
Vol 113 (17) ◽  
pp. 173511 ◽  
Author(s):  
Zimu Zhu ◽  
David A. Romero ◽  
Daniel P. Sellan ◽  
Aydin Nabovati ◽  
Cristina H. Amon
Keyword(s):  
Lattice Dynamics ◽  
Relaxation Times ◽  
Holland Model

Assessment of the Holland Model for Silicon Phonon-Phonon Relaxation Times Using Lattice Dynamics Calculations

2011 ◽  
Author(s):  
Zimu Zhu ◽  
Daniel P. Sellan ◽  
Aydin Nabovati ◽  
Cristina H. Amon
Keyword(s):  
Thermal Conductivity ◽  
Lattice Dynamics ◽  
Relaxation Times ◽  
Holland Model ◽  
Bulk Thermal Conductivity ◽  
Thermal Conductivities

We assess the ability of the Holland model to accurately predict phonon-phonon relaxation times from bulk thermal conductivity values. Lattice dynamics calculations are used to obtain phonon-phonon relaxation times and thermal conductivities for temperatures ranging from 10 to 1000 K for Stillinger-Weber silicon. The Holland model is then fit to these thermal conductivities and used to predict relaxation times, which are compared to the relaxation times obtained by lattice dynamics calculations. We find that fitting the Holland model to both total and mode-dependent thermal conductivities does not result in accurate mode-dependent phonon-phonon relaxation times.

Analysis of Heat Conduction in Silicon Using Molecular Dynamics Simulations

2006 ◽  
Author(s):  
Asegun S. Henry ◽  
Gang Chen
Keyword(s):  
Molecular Dynamics ◽  
Lattice Dynamics ◽  
Crystalline Silicon ◽  
Relaxation Times ◽  
Normal Modes ◽  
Md Simulations ◽  
Dynamics Simulations ◽  
Technological Significance ◽  
Fitting Parameters ◽  
Phonon Properties

Silicon's material properties, have been studied extensively because of its technological significance in a variety of industries, including microelectronics. Yet, questions surrounding the phonon relaxation times in silicon continue to linger.1,2 Previous theoretical works3-5 have generated qualitative expressions for phonon relaxation times, however these approaches require fitting parameters that cannot be determined reliably. This paper first discusses implementation issues associated with using the Green-Kubo method in molecular dynamics (MD) simulations. We compare various techniques used in similar works and discusses several implementation issues that have arisen in the literature. We then describe an alternative procedure for analyzing the normal modes of a crystal to extract phonon relaxation times. As an example material we study bulk crystalline silicon using equilibrium MD simulations and lattice dynamics. The environment dependent interatomic potential6 is used to model the interactions and frequency dependent phonon properties are extracted from the MD simulations.

Predicting Phonon Properties From Molecular Dynamics Simulations Using the Spectral Energy Density

2011 ◽  
Author(s):  
Joseph E. Turney ◽  
John A. Thomas ◽  
Alan J. H. McGaughey ◽  
Cristina H. Amon
Keyword(s):  
Molecular Dynamics ◽  
Energy Density ◽  
Molecular Dynamics Simulations ◽  
Lattice Dynamics ◽  
Relaxation Times ◽  
Mode Analysis ◽  
Spectral Energy ◽  
Spectral Energy Density ◽  
Dynamics Simulations ◽  
Phonon Properties

Using lattice dynamics theory, we derive the spectral energy density and the relation between the spectral energy density and the phonon frequencies and relaxation times. We then calculate the spectral energy density and phonon frequencies and relaxation times for a test system of Lennard-Jones argon using velocities obtained from molecular dynamics simulations. The phonon properties, which can be used to calculate thermal conductivity, are compared to predictions made using (i) anharmonic lattice dynamics calculations and (ii) a technique that performs normal mode analysis on the positions and velocities obtained from molecular dynamics simulations.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Crystal structure and lattice dynamics of hydrogen-loaded austenitic steel

2003 ◽  
Vol 112 ◽  
pp. 407-410
Author(s):  
S. A. Danilkin ◽  
M. Hölzel ◽  
H. Fuess ◽  
H. Wipf ◽  
T. J. Udovic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Austenitic Steel ◽  
Lattice Dynamics

INVESTIGATION OF LATTICE DYNAMICS WITH117Sn AND119Sn

1974 ◽  
Vol 35 (C6) ◽  
pp. C6-375-C6-377
Author(s):  
W. MÜLLER ◽  
H. WINKLER ◽  
E. GERDAU
Keyword(s):  
Lattice Dynamics
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