Elastic constants and phonon frequencies of Si calculated by a fast full-potential linear-muffin-tin-orbital method

1988 ◽  
Vol 38 (2) ◽  
pp. 1537-1540 ◽  
Author(s):  
M. Methfessel
Keyword(s):  
Elastic Constants ◽  
Orbital Method ◽  
Full Potential ◽  
Linear Muffin Tin Orbital

FIRST-PRINCIPLES HIGH-PRESSURE ELASTIC AND THERMODYNAMIC PROPERTIES OF TANTALUM

2011 ◽  
Vol 25 (10) ◽  
pp. 1393-1407 ◽  
Author(s):  
JING-HE WU ◽  
XIAN-LIN ZHAO ◽  
YOU-LIN SONG ◽  
GUO-DONG WU
Keyword(s):  
Thermodynamic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Equations Of State ◽  
Debye Model ◽  
Thermal Expansivity ◽  
Orbital Method ◽  
Full Potential ◽  
Body Centered Cubic ◽  
Theoretical Results

The all-electron full-potential linearized muffin-tin orbital method, by means of quasi-harmonic Debye model, is applied to investigate the elastic constant and thermodynamic properties of body-centered-cubic tantalum (bcc Ta). The calculated elastic constants of bcc Ta at 0 K is consistent with the previous experimental and theoretical results. Our calculations give the correct trends for the pressure dependence of elastic constants. By using the convenient quasi-harmonic Debye model, we refined the thermal equations of state. The thermal expansivity and some other thermal properties agree well with the previous experimental and theoretical results.

Theoretical study of point defects in GaN and AlN; lattice relaxations and pressure effects

1997 ◽  
Vol 2 ◽  
Author(s):  
I. Gorczyca ◽  
A. Svane ◽  
N. E. Christensen
Keyword(s):  
Theoretical Calculations ◽  
Pressure Effects ◽  
Function Technique ◽  
Orbital Method ◽  
Full Potential ◽  
Cation Site ◽  
Carbon Impurity ◽  
Atomic Displacements ◽  
Cubic Gan ◽  
Linear Muffin Tin Orbital

Native defects and some common dopants (Mg, Zn, and C) in cubic GaN and AlN are examined by means of ab initio theoretical calculations using two methods: i) the Green's function technique based on the linear muffin-tin orbital method in the atomic-spheres approximation; ii) a supercell approach in connection with the full-potential linear muffin-tin-orbital method. We apply the first method to look mainly at the energetic positions of the defect and impurity states in different charge states and their dependence on hydrostatic pressure. The second method allows us to study lattice relaxations. Whereas small relaxations are found near vacancies and substitutional Mg and Zn, the calculations predict large atomic displacements around antisite defects and the substitutional carbon impurity on the cation site.

scholarly journals Program LMTART for electronic structure calculations

2005 ◽  
Vol 220 (5/6) ◽  
Author(s):  
Sergej Y. Savrasov
Keyword(s):  
Electronic Structure ◽  
Computer Program ◽  
Electronic Structure Calculations ◽  
Orbital Method ◽  
Full Potential ◽  
Structure Calculations ◽  
Linear Muffin Tin Orbital

AbstractA computer program LMTART for electronic structure calculations using full potential linear muffin-tin orbital method is described.

scholarly journals Native defects and carbon impurity in cubic BN

1998 ◽  
Vol 3 ◽  
Author(s):  
I. Gorczyca ◽  
A. Svane ◽  
N. E. Christensen
Keyword(s):  
Electronic Structure ◽  
Lattice Relaxation ◽  
Function Technique ◽  
Orbital Method ◽  
Full Potential ◽  
Carbon Impurity ◽  
Native Defects ◽  
Relaxation Effects ◽  
Carbon Impurities ◽  
Linear Muffin Tin Orbital

Using the Green’s function technique based on the linear muffin-tin orbital method in the atomic-spheres approximation we study the electronic structure of native defects and substitutional carbon impurities in cubic BN. To include the lattice relaxation effects a supercell approach in connection with the full-potential linear muffin-tin-orbital method is applied.

Elastic Constants and Related Properties of the Group III-Nitrides

1995 ◽  
Vol 395 ◽  
Author(s):  
Kwiseon Kim ◽  
Walter R. L. Lambrecht ◽  
B. Segall
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Bond Angle ◽  
Local Density ◽  
Group Iii Nitrides ◽  
Internal Displacement ◽  
Orbital Method ◽  
Model Parameters ◽  
Full Potential ◽  
Group Iii

ABSTRACTThe elastic constants of the Group-III nitrides, c-BN, AlN and GaN were calculated from first-principles using the full-potential linear muffin-tin orbital method and local density approximation. The relation between the elatic constants in zincblende and wurtzite is studied by means of a tensor coordinate transformation approach. The latter combined with a correction for the internal displacement of the rotated tetrahedra is found to provide good results for the Ch11Ch12 and Ch44 but not for Ch13 and Ch33. These two require explicit calculations involving distortions along the c-axis. The calculations also provide information on the transverse optical phonons. By deriving Keating model parameters we show that BN is much stiffer against bond-angle distortions than the other nitrides.

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