J. F. Justo

Isolated nickel impurities in diamond: A microscopic model for the electrically active centers

We present a theoretical investigation on the structural and electronic properties of isolated nickel impurities in diamond. The atomic structures, symmetries, formation and transition energies, and hyperfine parameters of isolated interstitial and substitutional Ni were computed using ab initio total energy methods. Based on our results, we ultimately propose a consistent microscopic model which explains several experimentally identified nickel-related active centers in diamond.

Role of intrinsic defects in the electronic and optical properties of α-HgI2

We investigated the role of intrinsic defects in the electronic and optical properties of mercuric iodide using ab initio methods. The calculations were performed using the total energy all electron methodology, considering full atomic relaxation. We computed the band structure, spin, formation and transition energies, and the dielectric function of isolated iodine and mercury vacancies in several charge states. Our results were compared to available experimental data on photoluminescence and photoplasticity in HgI2. We propose a microscopic model which can explain most of the data on those luminescent centers, unifying experimental results which suggested conflicting conclusions.

Effects of extended defects on the properties of intrinsic and extrinsic point defects in silicon

Abstract We investigated the interaction of intrinsic and extrinsic point defects with stacking faults in silicon. The calculations were carried out using ab initio total energy methods. The results show that the formation energies of intrinsic defects and impurities (P, As, and Al) are lower at the stacking fault as compared to the respective defects in crystalline environment. Therefore, stacking faults should have a large concentration of defects, and they should play an important role on the mechanisms of dislocation motion.

3 d transition metal impurities in diamond: Electronic properties and chemical trends

First principles calculations have been used to investigate the trends on the properties of isolated 3

Interaction of As impurities with 30° partial dislocations in Si: An ab initio investigation

d

Dislocation core reconstruction in zinc-blende semiconductors

transition metal impurities (from Sc to Cu) in diamond. Those impurities have small formation energies in the substitutional or double semivacancy sites and large energies in the interstitial site. Going from Sc to Cu, the 3

Crystal engineering using functionalized adamantane

d

Electronic charge effects on dislocation cores in silicon

-related energy levels in the band gap move from the top of the band gap toward the valence band in all three sites. Trends in electronic properties and transition energies of the impurities, in the substitutional or interstitial sites, are well described by a simple microscopic model considering the electronic occupation of the 3

Arsenic segregation, pairing and mobility on the cores of partial dislocations in silicon

d

A first principles investigation of mercuric iodide: bulk properties and intrinsic defects

-related levels. On the other hand, for the impurities in the double semivacancy site, there is a weak interaction between the divacancy- and the 3