scholarly journals Comparison of the projector augmented-wave, pseudopotential, and linearized augmented-plane-wave formalisms for density-functional calculations of solids

1997 ◽  
Vol 55 (4) ◽  
pp. 2005-2017 ◽  
Author(s):  
N. A. W. Holzwarth ◽  
G. E. Matthews ◽  
R. B. Dunning ◽  
A. R. Tackett ◽  
Y. Zeng
2012 ◽  
Vol 23 (06) ◽  
pp. 1250043 ◽  
Author(s):  
BAKHTIAR UL HAQ ◽  
A. AFAQ ◽  
R. AHMED ◽  
S. NASEEM

A density functional study for structural and electronic properties of Zinc Oxide (ZnO), in wurtzite, rock salt and zinc-blende phases has been performed using full potential-linearized augmented plane wave/linearized augmented plane wave plus local ideal orbital (FP-LAPW/L(APW+lo) approach as realized in WIEN2k code. To approximate exchange correlation energy and corresponding potential, a special GGA parameterized by Wu–Cohen has been implemented. Our results of lattice constants, bulk moduli as well as for internal parameter with GGA-WC are found to be more reliable. This study reveals that value of internal parameter decreases with increasing volume whereas computed electronic band structure confirms the direct band gap behavior of ZnO in B4 and B3 phases while indirect band gap behavior in B1 phase. Moreover, two fold degeneracy at the maxima of valence band for B4 and B1 phases whereas three fold for B3 is observed. A detailed comparison with experimental and other first principles studies is also made.


Author(s):  
Ekta Jain ◽  
Gitanjali Pagare ◽  
Sankar P. Sanyal

An ab-initio investigation on structural, electronic, optical, elastic and thermal properties of CuZr intermetallic compound using full-potential linearized augmented plane wave method in the support of density functional theory at ambient condition have been performed. We have employed the generalized gradient approximation of (PBE) to indulgence the exchange correlation potential by solving Kohn-Sham equations. Total energy of CuZr as a function of the unit cell volume has been calculated using full potential linearized augmented plane wave (FP-LAPW) method in B1, B2 and B3 crystal structure to obtain the ground state properties. The study of different phases regarding their enthalpy vs. pressure variation is also presented. Our calculated structural parameters (a0 = 3.268 Å, B = 119 GPa and B' = 4.95) of CuZr are consistent with both the available experimental (a0 = 3.262 Å) and previously presented theoretical data (a0 = 3.280 Å, B = 121 GPa) for B2-type (CsCl) crystal structure. The results obtained from density of states (DOS) and optical spectra shows that the present compound is metallic. The value of density of states at the Fermi level N (EF) is found to 3.89 states/eV which is determined due to the contribution of ‘d’ like states of Cu and Zr and ‘p’ like states of Zr atom. The second order elastic constants are comparatively studied and an excellent agreement is found with other theoretical data. The trend of calculated elastic constants i.e. C11 - C12 > 0, C11 > 0, C44 > 0, C11 + 2C12 > 0 shows the stability criteria for B2-type (CsCl) crystal structure at ambient pressure. The sound velocities for longitudinal and shear waves, Debye average velocity and Debye temperature have been successfully calculated as a first theoretical prediction.


2002 ◽  
Vol 727 ◽  
Author(s):  
A. M. Mazzone

AbstractFull Potential Linearized Augmented Plane Wave calculations have been performed for epitaxial multilayers formed by the noble metals Ag and Cu with a thickness n up to 10 layers. The multilayers have a fcc lattice and are pure or compositionally modulated with a structure of the type Agn Cun or (AgCu)n. For n in the range 2,3 the density of states, evaluated at paramagnetic level, exhibits a sharp reduction of the bandwidth which is consistent with the reduced coordination of these structures. For n ≤ 5 the density of states in the central layers converges to the bulk value while the outer layers retain the narrow bandwidth found at n=2. Due to the absence of charge intermixing and hybridization, these features are shared by multilayers of all composition.


2011 ◽  
Vol 115 (50) ◽  
pp. 14484-14494 ◽  
Author(s):  
Emmanuel Aubert ◽  
Sébastien Lebègue ◽  
Martijn Marsman ◽  
Thai Thanh Thu Bui ◽  
Christian Jelsch ◽  
...  

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