Linear muffin-tin orbital method LMTO

There are a number of band-structure methods that make varying approximations in the solution of the Kohn-Sham equations. They are described in detail by Godwal et al. (1983) and Srivastava and Weaire (1987), and we shall discuss them only briefly. For each method, one must eon-struct Bloch functions delocalized by symmetry over all the unit cells of the solid. The methods may be conveniently divided into (1) pesudopo-tential methods, (2) linear combination of atomic orbital (LCAO) methods (3) muffin-tin methods, and (4) linear band-structure methods. The pseudopotential method is described in detail by Yin and Cohen (1982) the linear muffin-tin orbital method (LMTO) is described by Skriver (1984) the most advanced of the linear methods, the full-potential linearized augmented-plane-wave (FLAPW) method, is described by Jansen... 

The band structure of CeCu2Si2 and of the isostructural LaCu2Si2 was calculated using the self-consistent semirelativistic, linear Muffin-tin orbital method (LMTO) (Andersen 1975, Jarlborg and Arbman 1977). The Ce-4f levels are situated mainly above the Fermi energy E. The density-of-states at is large and heavily concentrated around the Ce-4f band (Jarlborg et al. 1983). 

The calculated and measured electron effective mass m c and its k-dependency for WZ and ZB GaN and AIN are summarised in TABLES 1 and 2, respectively. Suzuki et al derived them with a full-potential linearised augmented plane wave (FLAPW) band calculation [4,5], Miwa et al used a pseudopotential mixed basis approach to calculate them [6]. Kim et al [7] determined values for WZ nitrides by the full-potential linear muffin-tin orbital (FP-LMTO) method. Majewski et al [8] and Chow et al [9,10] used the norm-conserving pseudo-potential plane-wave (PPPW) method. Chen et al [11] also used the FLAPW method to determine values for WZ GaN, and Fan et al obtained values for ZB nitrides by their empirical pseudo-potential (EPP) calculation [12],... 

Note A/B implies A grown or strained to B and vice versa. A B implies no growth direction or explicit strain dependence, i.e. natural. ) T = theoretical E = experimental AVL = average lattice XPS = X-ray photoelectron spectroscopy PL = photoluminescence CL = cathodoluminescence UPS = ultraviolet photoelectron spectroscopy LMTO = linear muffin tin orbital method LAPW = linearised augmented plane wave method PWP = plane wave pseudopotential method VCA = virtual crystal approximation. 

T = theoretical LMTO = linear muffin tin orbital method. 

In Chap.5 we derive the LCMTO equations in a form not restricted to the atomic-sphere approximation, and use the , technique introduced in Chap.3 to turn these equations into the linear muffin-tin orbital method. Here we also give a description of the partial waves and the muffin-tin orbitals for a single muffin-tin sphere, define the energy-independent muffin-tin orbitals and present the LMTO secular matrix in the form used in the actual programming, Sect.9.3. 

AE-LMTO All-electron tight-binding linear muffin-tin orbitals method AF Antiferromagnetic... 

AEI Atomic exchange interaction (model) LMTO Linear muffin-tin orbital (method)... 

By using the tight-binding linearized muffin-tin orbital method combined with die coherent-potential approximation (TB-LMTO-CPA) the total energies, bulk moduli, equilibrium lattice parameters, magnetie moments, and hyperfine fields of bcc solid solution were ealeulated by [2000San], and are in qualitative agreement with experimental trends. 

All calcidations have been performed within LDA+U with the same value of U as used for pure -Pu (3.13 eV) in fire fiiamework of the hill-potential linear-muffin-tin-orbital (FP-LMTO) method with von Barth-Hedin exchange-correlation potential and spin-orbit coupling. We only presait preliminary results where the antiferromagnetic configuration was not yet taken into account. 

We use the full-potential linear-muffin-tin-orbital (FP-LMTO) method [17-19] to calculate formation energies of different compounds in the Al-Zr binary system, all based on a fee lattice. Details of ab initio calculation can be found in appendix A. They are the same as in our previous work [20], except the fact that we use the generalized gradient approximation (GGA) instead of the local density approximation (LDA) for the exchange-correlation functional. 

In order to comprehensively show the chemical dissociation process of CO on metal surfaces, electronic structure calculations have been performed for simple models. We have chosen two methods for the present analyses. The first method is the Discrete Variational Xa (DV-Xa) method, which is the first-principles molecular orbital calculation using Slater s Xa fimctional for the electron many body term [21]. This method is applied for the electronic structural analyses of CO adsorption on metal surfaces. The second method is the Full-Potential Linear Muffin-Tin Orbital (FP-LMTO) method, which is the first-principles band structure calculation method [22]. The FP-LMTO implementation code of LmtART [23, 24] is used for the calculations of the density of states (DOS) of non-magnetic fee iron phase. We discuss the electronic structure of transition metal alloys from the rigid band analyses using this DOS. The local density approximation (LDA) parameterized by Vosko et al. [25] is used for the present FP-LMTO calculations. The tetrahedron... 

We have used the basis set of the Linear-Muffin-Tin-Orbital (LMTO) method in the atomic sphere approximation (ASA). The LMTO-ASA is based on the work of Andersen and co-workers and the combined technique allows us to treat all phases on equal footing. To treat itinerant magnetism we have employed the Vosko-Wilk-Nusair parametrization for the exchange-correlation energy density and potential. In conjunction with this we have treated the alloying effects for random and partially ordered phases with a multisublattice generalization of the coherent potential approximation (CPA). 

Theoretical calculations were performed with the linear muffin tin orbital (LMTO) method and the local density approximation for exchange and correlation. This method was used in combination with supercell models containing up to 16 atoms to calculate the DOS. The LMTO calculations are run self consistently and the DOS obtained are combined with the matrix elements for the transitions from initial to final states as described in detail elsewhere (Botton et al., 1996a) according to the method described by Vvedensky (1992). A comparison is also made between spectra calculated for some of the B2 compounds using the Korringa-Kohn-Rostoker (KKR) method. 

A different approach was taken by Hao and Cooper (1994), who used a combination of the him linear muffin-tin orbital (LMTO) method and an ab initio molecular quantum cluster method, to investigate S02 adsorption on a Cu monolayer supported by 7—AI2O3. Emphasis here was on the geometry of adsorption sites, with the conclusion that the preferred adsorption site is the Al—Al bridging one. 

The results are conveniently and clearly expressed in a thermodynamic formalism this is why they find their place in this chapter. They depend however on parameters which are drawn from band-theory, especially from the LMTO-ASA (Linear Muffin-Tin Orbitals-Atomic Sphere Approximation) method. 

In this paper we present preliminary results of an ab-initio study of quantum diffusion in the crystalline a-AlMnSi phase. The number of atoms in the unit cell (138) is sufficiently small to permit computation with the ab-initio Linearized Muffin Tin Orbitals (LMTO) method and provides us a good starting model. Within the Density Functional Theory (DFT) [15,16], this approach has still limitations due to the Local Density Approximation (LDA) for the exchange-correlation potential treatment of electron correlations and due to the approximation in the solution of the Schrodinger equation as explained in next section. However, we believe that this starting point is much better than simplified parametrized tight-binding like s-band models. 

To probe the electronic structures of the materials in the solid state, band structure calculations on the crystal structure of compound 22 were carried out. The results obtained by using the linear muffin-tin orbital (LMTO) self-consistent field (SCF) method support the interpretation that compounds 22 (R1 = Me, Et R2 = H) are small-band-gap semiconductors. 

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