Calculation of Phonon Dispersion for 3d Transition Metals Cr and Fe by Modified Analytic Embedded Atom Method

2011 ◽  
Vol 411 ◽  
pp. 532-536
Author(s):  
You Xie ◽  
Jian Min Zhang
Keyword(s):  
Experimental Data ◽  
Transition Metals ◽  
Phonon Frequency ◽  
Phonon Dispersion ◽  
Phonon Dispersion Curve ◽  
Embedded Atom Method ◽  
Body Centered Cubic ◽  
Phonon Dispersion Curves ◽  
Embedded Atom ◽  
Good Agreement

The modified analytical embedded atom method is applied to calculate the phonon dispersion of body-centered cubic 3d transition metals Cr and Fe along five symmetry directions [q 0 0], [1 q q], [q q q], [q q 0] and [1/2 1/2 q]. Our results of phonon dispersion curves are in good agreement with the available experimental data. For the two transition metals Cr and Fe, along the same direction, a similar phonon dispersion curve is obtained in spite of the phonon frequency decreases for Cr and Fe due to the atom mass increases. There are no experimental results for comparison along the directions [1 q q] and [1/2 1/2 q], further experimental measurement are needed.

CALCULATION OF PHONON DISPERSION FOR TRANSITION METALS V, Nb AND Ta

2011 ◽  
Vol 25 (29) ◽  
pp. 4047-4053 ◽  
Author(s):  
YOU XIE ◽  
JIAN-MIN ZHANG
Keyword(s):  
Transition Metals ◽  
Lattice Dynamics ◽  
Phonon Frequency ◽  
Phonon Dispersion ◽  
Atomic Mass ◽  
The Other ◽  
Embedded Atom Method ◽  
High Symmetry ◽  
Embedded Atom ◽  
Good Agreement

Combining the modified analytic embedded atom method (MAEAM) with lattice dynamics theory, the phonon dispersion along five symmetry directions have been calculated for three transition metals V, Nb and Ta . A good agreement between calculations and experiments along three high symmetry directions [q00], [qqq] and [qq0] implies that the predicted phonon dispersion along the other two directions [1qq] and [Formula: see text] are well behaved. Along each direction, the phonon frequency decreases for V, Nb and Ta successively may be related to the ratio of the cohesive energy to atomic mass.

Atomistic simulation of phonon dispersion for body-centred cubic alkali metals

2008 ◽  
Vol 86 (6) ◽  
pp. 801-805 ◽  
Author(s):  
Y Xie ◽  
J -M Zhang
Keyword(s):  
Cohesive Energy ◽  
Atomistic Simulation ◽  
Alkali Metals ◽  
Phonon Frequency ◽  
Phonon Dispersion ◽  
Atomistic Simulations ◽  
Phonon Dispersion Curves ◽  
Embedded Atom ◽  
Atomic Force ◽  
Good Agreement

Atomistic simulations of phonon dispersion for body-centred cubic alkali metals were carried out using the modified analytic embedded atom potentials. The expressions for atomic force constants are derived, the cohesive energy and elastic constants are calculated, and the phonon dispersion curves of Li, Na, K, Rb, and Cs are calculated along five principal symmetry directions. The calculated results are in good agreement with the available experiments. For all of the five alkali metals, in the same direction, a similar phonon dispersion curve is obtained in spite of the successive phonon frequency decreases for Li, Na, K, Rb, and Cs, which may be related to the atom mass increases or the cohesive energy decreases. PACS Nos.: 63.20.Dj, 71.20.Dg, 31.15.Ct

The application of the analytic embedded atom method to bcc metals and alloys

1992 ◽  
Vol 7 (3) ◽  
pp. 639-652 ◽  
Author(s):  
A.M. Guellil ◽  
J.B. Adams
Keyword(s):  
Thermal Expansion ◽  
Predictive Power ◽  
Phonon Dispersion ◽  
Embedded Atom Method ◽  
Phonon Dispersion Curves ◽  
Fcc Metals ◽  
Surface Energies ◽  
Bcc Metals ◽  
Embedded Atom ◽  
And Migration

Johnson and Oh have recently developed Embedded Atom Method potentials for bcc metals (Na, Li, K, V, Nb, Ta, Mo, W, Fe). The predictive power of these potentials was first tested by calculating vacancy formation and migration energies. Due to the results of these calculations, some of the functions were slightly modified to improve their fit to vacancy properties. The modified potentials were then used to calculate phonon dispersion curves, surface relaxations, surface energies, and thermal expansion. In addition, Johnson's alloy model, which works well for fcc metals, was applied to the bcc metals to predict dilute heats of solution.

End Processing of MAEAM Pair Potential for BCC Metals

2012 ◽  
Vol 424-425 ◽  
pp. 568-572
Author(s):  
Hak Son Jin ◽  
An Du
Keyword(s):  
Phonon Dispersion ◽  
Pair Potential ◽  
Embedded Atom Method ◽  
Model Calculations ◽  
Phonon Dispersion Curves ◽  
Bcc Metals ◽  
Embedded Atom ◽  
Body Potential ◽  
Multi Body ◽  
Potential Parameters

An end processing function of the pair-potential of modified analytical embedded atom method (MAEAM) was suggested for bcc metals. Through fitting the elastic constants, cohesive energy and an equilibrium condition of bcc metal crystals correctly, we changed the pair-potential parameters and the modification term parameter of the multi-body potential. The model calculations fully demonstrate the structure stabilities and the phonon dispersion curves of seven bcc transition metals: Cr, Fe, Mo, Nb, Ta, V and W.

Self-diffusion and impurity diffusion of fee metals using the five-frequency model and the Embedded Atom Method

1989 ◽  
Vol 4 (1) ◽  
pp. 102-112 ◽  
Author(s):  
J. B. Adams ◽  
S. M. Foiles ◽  
W. G. Wolfer
Keyword(s):  
Experimental Data ◽  
Transition Metals ◽  
Activation Energies ◽  
Embedded Atom Method ◽  
Vacancy Mechanism ◽  
Frequency Model ◽  
Self Diffusion ◽  
Embedded Atom ◽  
Diffusion Rates ◽  
Jump Frequencies

The activation energies for self-diffusion of transition metals (Au, Ag, Cu, Ni, Pd, Pt) have been calculated with the Embedded Atom Method (EAM); the results agree well with available experimental data for both mono-vacancy and di-vacancy mechanisms. The EAM was also used to calculate activation energies for vacancy migration near dilute impurities. These energies determine the atomic jump frequencies of the classic “five-frequency formula,” which yields the diffusion rates of impurities by a mono-vacancy mechanism. These calculations were found to agree fairly well with experiment and with Neumann and Hirschwald's “Tm” model.

Influence of the static electron gas screening function on the lattice dynamics of sodium

1970 ◽  
Vol 48 (2) ◽  
pp. 183-192 ◽  
Author(s):  
D. J. W. Geldart ◽  
Roger Taylor ◽  
Y. P. Varshni
Keyword(s):  
Distribution Function ◽  
Lattice Dynamics ◽  
Phonon Frequency ◽  
Phonon Dispersion ◽  
Electron Gas ◽  
Phonon Dispersion Curves ◽  
X Ray ◽  
Debye Temperatures ◽  
Static Electron ◽  
Good Agreement

The static electron gas screening function calculated by Geldart and Taylor has been used in conjunction with the theory of Vosko, Taylor, and Keech to calculate the phonon dispersion curves, the effective calorimetric and X-ray Debye temperatures, and moments of the phonon frequency distribution function of sodium. The results which compare very favorably with those obtained using other screening functions give good agreement with experiment, indicating that the new screening function is reasonably adequate for calculations in sodium.

The crystal dynamics of cuprous halides

1982 ◽  
Vol 60 (11) ◽  
pp. 1589-1594 ◽  
Author(s):  
Manvir S. Kushwaha
Keyword(s):  
Phonon Dispersion ◽  
Characteristic Temperature ◽  
Force Model ◽  
Phonon Dispersion Curves ◽  
Debye Characteristic Temperature ◽  
Zinc Blende ◽  
Crystal Dynamics ◽  
Bond Bending ◽  
Dynamical Description ◽  
Good Agreement

The lattice dynamics of cuprous halides have been thoroughly investigated by means of an 8-parameter bond-bending force model (BBFM), recently developed and applied successfully to study phonons in various II–VI and III–V compound semiconductors having zinc-blende (ZB) structure. The application of BBFM is made to calculate the phonon dispersion relations, phonon density of states, and temperature variation of the Debye characteristic temperature [Formula: see text] of CuCl, CuBr, and CuI. The room-temperature neutron scattering measurements for phonon dispersion curves along three principal symmetry directions and calorimetric experimental data for the Debye characteristic temperature have been used to check the validity of BBFM for the three crystals. The overall good agreement between theoretical and experimental results supports its use as an appropriate model for the dynamical description of ZB crystals.

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