Lucy Assali - Academia.edu (original) (raw)

Papers by Lucy Assali

Research paper thumbnail of Propriedades físicas do diamante puro e com impurezas de Ni

Research paper thumbnail of Chemical Trends in Electronic Properties of Arsenic Vacancy-3d Transition Metal Pairs in Gallium Arsenide

Materials Science Forum, 1997

ABSTRACT

Research paper thumbnail of Electronic Structure of Copper-Related Defects in Germanium

Materials Science Forum, 1994

Research paper thumbnail of Electronic States of Copper-Related Impurities in Germanium

Brazilian Journal of Physics, 1994

... WM Orellana and LVC Assali impurities through a 27-atom cluster. ... g/A _ _'>i_.4p t... more ... WM Orellana and LVC Assali impurities through a 27-atom cluster. ... g/A _ _'>i_.4p ta-—O—Q1l1__:7¢'__t_._._._ .»'\' x 2 E ' I .7 ~\ V /////O—O1<'(K/////fi : 'S K' if' 01* t (d) ~3d e(d) Figure 5: Schematic representation of the impurity levels of the 16Ge + Gus cluster as ...

Research paper thumbnail of Manganese and iron impurities in gallium nitride

Research paper thumbnail of Influence of Van der Waals interaction on the thermodynamics properties of NaCl

Research paper thumbnail of Calcium carbonate at high pressures and high temperatures: A first-principles investigation

Physics of the Earth and Planetary Interiors, 2020

Research paper thumbnail of Stability of calcium and magnesium carbonates at Earth's lower mantle thermodynamic conditions

Earth and Planetary Science Letters, 2019

Research paper thumbnail of Importance of van der Waals interaction on structural, vibrational, and thermodynamic properties of NaCl

Solid State Communications, 2018

Research paper thumbnail of Iron and manganese-related magnetic centers in hexagonal silicon carbide: A possible roadmap for spintronic devices

Journal of Applied Physics, 2015

The electronic and magnetic properties of manganese- and iron-doped 4H-SiC were investigated by f... more The electronic and magnetic properties of manganese- and iron-doped 4H-SiC were investigated by first-principles calculations, using an all electron methodology. The results on stability, spin configurations, formation and transition energies, local magnetic moments, and hyperfine parameters were compared to available theoretical and experimental data. The results indicated that transition metal impurities are energetically more favorable in lattice sites with carbon atoms as their first nearest neighbors, in both substitutional and interstitial configurations, which results from the larger electronegativity of carbon with respect to that of silicon. The analysis of the electronic properties of those impurity centers showed that they could stay in several stable charge states, depending on the Fermi energy level position within the host SiC bandgap. Additionally, by computing the p-d exchange coupling constant, which is related to a spin polarization in the SiC valence band top, we ...

Research paper thumbnail of Mechanism for hydrogen-enhanced oxygen diffusion in silicon

Research paper thumbnail of Electronic structure of complex defects in silicon

Lecture Notes in Physics

Ab initio self-consistent-field electronic state calculations are carried out for transition meta... more Ab initio self-consistent-field electronic state calculations are carried out for transition metal-related and hydrogen-related complexes in silicon. The first theoretical investigation of the chemical trends in electronic properties of transition metal impurity pair complexes in a semiconductor is reported. Chemical trends in the electronic structure of pair complexes involving a boron atom and a transition metal impurity in silicon are also investigated. Results are presented for the hydrogen-boron and hydrogen-carbon complexes in silicon and attempts are made to explain the electrical properties of these systems. The calculations do not provide support for the currently accepted ionic model where the pair is described as two electrostatically bound point charges.

Research paper thumbnail of Theoretical Model of Transition Metal-Shallow Acceptor Impurity Pairs in Silicon

Materials Science Forum, 1986

Research paper thumbnail of Electronic States of Fe<sub>4</sub> and Mn<sub>4</sub> Clusters in Silicon

Materials Science Forum, 1992

Research paper thumbnail of Manganese Impurity in Boron Nitride and Gallium Nitride

Materials Science Forum, 2005

We carried out a theoretical investigation on the properties of manganese impurity centers in cub... more We carried out a theoretical investigation on the properties of manganese impurity centers in cubic boron and gallium nitrides. The calculations were performed using the all electron spin-polarized full-potential linearized augmented plane wave methodology. Our results indicate that manganese in boron nitride, in a neutral charge state, is energetically more favorable in a divacancy site as compared to a substitutional cation site. We present the results on stability, spin states, impurity magnetic moment, hyperfine parameters, and formation and transition energies of manganese at the divacancy site in several charge states.

Research paper thumbnail of 3d-Transition Metals in Cubic and Hexagonal Silicon Carbide

Materials Science Forum, 2005

The electronic and structural properties of isolated 3d-transition metal impurities in 3C, 4H, an... more The electronic and structural properties of isolated 3d-transition metal impurities in 3C, 4H, and 2H silicon carbide have been investigated bytotal energy ab initio methods. The stability, spin states and transition energies of substitutional (Si sub-lattice) Cr, Mn, and Fe impurities in several charge states were computed. Our results are discussed in the context of available experimental data.

Research paper thumbnail of Nickel-Vacancy Complexes in Diamond: An Ab-Initio Investigation

Materials Science Forum, 2005

The electronic and structural properties of nickel-vacancy complexes in diamond were investigated... more The electronic and structural properties of nickel-vacancy complexes in diamond were investigated by a total energy ab initio methodology. These results are discussed in the context of the electrically active centers, commonly found in synthetic diamond.

Research paper thumbnail of Defect-molecule parameters for the divacancy in silicon

Solid State Communications, 1985

Research paper thumbnail of Microscopic models of Hg+, Auo and Pt- isoelectronic interstitial impurities in silicon

Solid State Communications, 1985

Research paper thumbnail of Microscopic Mechanism of Hydrogen Passivation of Acceptor Shallow Levels in Silicon

Physical Review Letters, 1985

Research paper thumbnail of Propriedades físicas do diamante puro e com impurezas de Ni

Research paper thumbnail of Chemical Trends in Electronic Properties of Arsenic Vacancy-3d Transition Metal Pairs in Gallium Arsenide

Materials Science Forum, 1997

ABSTRACT

Research paper thumbnail of Electronic Structure of Copper-Related Defects in Germanium

Materials Science Forum, 1994

Research paper thumbnail of Electronic States of Copper-Related Impurities in Germanium

Brazilian Journal of Physics, 1994

... WM Orellana and LVC Assali impurities through a 27-atom cluster. ... g/A _ _'>i_.4p t... more ... WM Orellana and LVC Assali impurities through a 27-atom cluster. ... g/A _ _'>i_.4p ta-—O—Q1l1__:7¢'__t_._._._ .»'\' x 2 E ' I .7 ~\ V /////O—O1<'(K/////fi : 'S K' if' 01* t (d) ~3d e(d) Figure 5: Schematic representation of the impurity levels of the 16Ge + Gus cluster as ...

Research paper thumbnail of Manganese and iron impurities in gallium nitride

Research paper thumbnail of Influence of Van der Waals interaction on the thermodynamics properties of NaCl

Research paper thumbnail of Calcium carbonate at high pressures and high temperatures: A first-principles investigation

Physics of the Earth and Planetary Interiors, 2020

Research paper thumbnail of Stability of calcium and magnesium carbonates at Earth's lower mantle thermodynamic conditions

Earth and Planetary Science Letters, 2019

Research paper thumbnail of Importance of van der Waals interaction on structural, vibrational, and thermodynamic properties of NaCl

Solid State Communications, 2018

Research paper thumbnail of Iron and manganese-related magnetic centers in hexagonal silicon carbide: A possible roadmap for spintronic devices

Journal of Applied Physics, 2015

The electronic and magnetic properties of manganese- and iron-doped 4H-SiC were investigated by f... more The electronic and magnetic properties of manganese- and iron-doped 4H-SiC were investigated by first-principles calculations, using an all electron methodology. The results on stability, spin configurations, formation and transition energies, local magnetic moments, and hyperfine parameters were compared to available theoretical and experimental data. The results indicated that transition metal impurities are energetically more favorable in lattice sites with carbon atoms as their first nearest neighbors, in both substitutional and interstitial configurations, which results from the larger electronegativity of carbon with respect to that of silicon. The analysis of the electronic properties of those impurity centers showed that they could stay in several stable charge states, depending on the Fermi energy level position within the host SiC bandgap. Additionally, by computing the p-d exchange coupling constant, which is related to a spin polarization in the SiC valence band top, we ...

Research paper thumbnail of Mechanism for hydrogen-enhanced oxygen diffusion in silicon

Research paper thumbnail of Electronic structure of complex defects in silicon

Lecture Notes in Physics

Ab initio self-consistent-field electronic state calculations are carried out for transition meta... more Ab initio self-consistent-field electronic state calculations are carried out for transition metal-related and hydrogen-related complexes in silicon. The first theoretical investigation of the chemical trends in electronic properties of transition metal impurity pair complexes in a semiconductor is reported. Chemical trends in the electronic structure of pair complexes involving a boron atom and a transition metal impurity in silicon are also investigated. Results are presented for the hydrogen-boron and hydrogen-carbon complexes in silicon and attempts are made to explain the electrical properties of these systems. The calculations do not provide support for the currently accepted ionic model where the pair is described as two electrostatically bound point charges.

Research paper thumbnail of Theoretical Model of Transition Metal-Shallow Acceptor Impurity Pairs in Silicon

Materials Science Forum, 1986

Research paper thumbnail of Electronic States of Fe<sub>4</sub> and Mn<sub>4</sub> Clusters in Silicon

Materials Science Forum, 1992

Research paper thumbnail of Manganese Impurity in Boron Nitride and Gallium Nitride

Materials Science Forum, 2005

We carried out a theoretical investigation on the properties of manganese impurity centers in cub... more We carried out a theoretical investigation on the properties of manganese impurity centers in cubic boron and gallium nitrides. The calculations were performed using the all electron spin-polarized full-potential linearized augmented plane wave methodology. Our results indicate that manganese in boron nitride, in a neutral charge state, is energetically more favorable in a divacancy site as compared to a substitutional cation site. We present the results on stability, spin states, impurity magnetic moment, hyperfine parameters, and formation and transition energies of manganese at the divacancy site in several charge states.

Research paper thumbnail of 3d-Transition Metals in Cubic and Hexagonal Silicon Carbide

Materials Science Forum, 2005

The electronic and structural properties of isolated 3d-transition metal impurities in 3C, 4H, an... more The electronic and structural properties of isolated 3d-transition metal impurities in 3C, 4H, and 2H silicon carbide have been investigated bytotal energy ab initio methods. The stability, spin states and transition energies of substitutional (Si sub-lattice) Cr, Mn, and Fe impurities in several charge states were computed. Our results are discussed in the context of available experimental data.

Research paper thumbnail of Nickel-Vacancy Complexes in Diamond: An Ab-Initio Investigation

Materials Science Forum, 2005

The electronic and structural properties of nickel-vacancy complexes in diamond were investigated... more The electronic and structural properties of nickel-vacancy complexes in diamond were investigated by a total energy ab initio methodology. These results are discussed in the context of the electrically active centers, commonly found in synthetic diamond.

Research paper thumbnail of Defect-molecule parameters for the divacancy in silicon

Solid State Communications, 1985

Research paper thumbnail of Microscopic models of Hg+, Auo and Pt- isoelectronic interstitial impurities in silicon

Solid State Communications, 1985

Research paper thumbnail of Microscopic Mechanism of Hydrogen Passivation of Acceptor Shallow Levels in Silicon

Physical Review Letters, 1985