In ultralow-k dielectric systems, the porous dielectrics are normally sealed by a SiC film before the deposition of a Ta diffusion barrier layer. However, the Ta barrier effects are negated when the SiC films are fabricated by plasma-enhanced chemical vapor deposition (PECVD). Through large... (Read more)

A method for local dynamic nuclear polarization is demonstrated in a GaAs/AlGaAs heterostructure at the Landau level filling factor ν=3. Using a narrow channel sample, where the width varies stepwise along the electron flow, the authors find that electron cooling (heating) causes the polarization... (Read more)

A defect whose electron transmission probability can be controlled by electric field is intentionally created on a metallic single-walled carbon nanotube (SWCNT) with a voltage pulse from a tip of an atomic force microscope (AFM). Localized characteristics of the created defect are elucidated with... (Read more)

Secondary ion mass spectrometry and photoluminescence are employed to evaluate the origin and efficiency of hydrogen passivation of nitrogen in GaNAs and GaNP. The hydrogen profiles are found to closely follow the N distributions, providing unambiguous evidence for their preferential binding as the... (Read more)

InP nanowires (NWs) were grown by gas source molecular beam epitaxy on InP (111)B substrates, using Au nanoparticles as a growth catalyst. The rod-shaped NWs exhibited hexagonal sidewall facets oriented along the {−211} family of crystal planes for all NW diameters, indicating minimal... (Read more)

The authors report on the generation of localized defects on single-walled carbon nanotubes by means of a hydrogen electron cyclotron resonance plasma. The defects have been investigated using scanning tunneling microscopy (STM) and show an apparent topographic height in the STM of 1–3 ... (Read more)

Radioactive ¹¹¹In atoms implanted into zinc oxide (ZnO) single crystals occupy substitutional Zn lattice sites after annealing to 700 °C. The respective photoluminescence (PL) spectra of the samples were monitored while the donor In decayed into stable and isolectronic Cd. The... (Read more)

Level set simulations of dislocation dynamics in biaxially strained, heteroepitaxial films reveal interesting kinetic and thermodynamic mechanisms for blocking the migration of threading dislocations. Two dislocations on the same or on intersecting slip planes may react to form a threading... (Read more)

The effect of the Schottky barrier height on the detection of the concentration of midgap defects using deep level transient spectroscopy (DLTS) is experimentally and theoretically studied for EH₆ and EH₇ defects in 4H-SiC. In this special case, the DLTS signal height... (Read more)

Defects present in ZnO nanocrystals prepared by a wet chemical method have been characterized by photoluminescence (PL) and positron annihilation spectroscopy (PAS) techniques. The as-prepared sample was heat treated at different temperatures to obtain nanocrystals in the size range of 19–39 ... (Read more)

We report on the thermal evolution of the deep levels in Fe implanted and annealed InP. The position and nature of the dominant traps have been assessed by current-voltage-temperature measurements analyzed in the framework of the space-charge-limited current model. For low temperature annealing the... (Read more)

Optical detection of magnetic resonance (ODMR) was used to study defects in ZnO substrates irradiated with 3 MeV electrons at room temperature. The Zn vacancy and some other ODMR centers were detected. Among these, the Zn vacancy and two other centers, labeled as LU3 and LU4, were also commonly... (Read more)

ZnO thin films prepared by pulsed laser deposition were implanted with phosphorous (P) using dose levels of 10¹²–10¹⁴ ions/cm² at room temperature. The P-implanted films were subsequently annealed between 500 and 700 °C in oxygen ambient. The Hall effect... (Read more)

Defects in ion-implanted GaN and their annealing properties were studied by using monoenergetic positron beams. Doppler broadening spectra of the annihilation radiation and the positron lifetimes were measured for Si⁺, O⁺, and Be⁺-implanted GaN grown by the... (Read more)

The effect of point defects on the copper (Cu)-related deep levels in p-type Czochralski (Cz) silicon has been investigated. It was found that generally five deep levels E_v+0.14 eV, E_v+0.17 eV, E_v+0.32 eV,... (Read more)

We have obtained a high concentration of P donor dopants in 6H-SiC enriched with ³⁰Si and irradiated with thermal neutrons. It was established that annealing at a relatively low temperature of 1300 °C, i.e., 500–600 °C lower than that used for annealing SiC with the... (Read more)

Bulk single crystals of unintentionally doped ZnO having charge carrier concentration, N_D−N_A values of ~10¹⁷ cm⁻³ were implanted with N⁺ ions at dosages of 10¹⁵ and 10¹⁶ ... (Read more)

Diffusion of sulfur (S) in S⁺ ion implanted Si(100) was investigated after rapid thermal annealing as well as after nickel silicidation. At lower S doses, S segregates to the Si(100) surface when the defects created by the S implantation are reduced during annealing. If the S dose... (Read more)

Fluorine-vacancy (FV) complexes have been directly observed in the Si_0.94Ge_0.06 layer in a Si-SiGe-Si structure, using variable-energy positron annihilation spectroscopy (VEPAS). These complexes are linked to the significant reduction of boron diffusion in the SiGe layer via... (Read more)

ZnO powders were synthesized by a precipitation method and annealed with carbon black. Electron paramagnetic resonance (EPR) and photoluminescence spectroscopies were conducted to study the characteristics of the ZnO powders. The g factor of the EPR signal shifted to lower value for the... (Read more)

We present deep level transient spectroscopy (DLTS) data measured on very high resistivity n-type float-zone silicon detectors after irradiation with 6 MeV electrons. The carbon interstitial annealing kinetics is investigated as a function of depth in the detector structure and related to... (Read more)

The isochronal annealing behavior of high energy (25–72 MeV) boron ion irradiation induced defects in boron-doped silicon is monitored through measurements of positron lifetimes and three distinct defect-evolution stages are identified. The initial boron doping created a defect environment... (Read more)

p-type 4H-SiC epitaxial layers grown by chemical vapor deposition have been implanted with 200 and 100 keV protons at five different implantation temperatures. An isochronal annealing series was performed from 100 to 1800 °C, and Al-doped epitaxial layers have been... (Read more)

The authors have investigated deep levels in as-grown and electron-irradiated p-type 4H-SiC epilayers by deep level transient spectroscopy. In as-grown epilayers, the D center and four deep levels are observed. In p-type 4H-SiC, reactive ion etching followed by thermal treatment (at... (Read more)

Electron paramagnetic resonance (EPR) has been used to monitor photoinduced changes in the charge states of deep transition-metal donors (Mn, Fe, Co, and Ni), shallow donors (Al and Ga), and lithium acceptors in a hydrothermally grown ZnO crystal. All of these impurities except the lithium were... (Read more)

An n-type hydrothermally grown ZnO sample becomes semi-insulating (ρ~10⁸ Ω cm) after 1-MeV electron-irradiation. Deep traps produced by the irradiation were studied by thermally stimulated current spectroscopy. The dominant trap in the as-grown sample has an activation... (Read more)

The effect of hydrogen implantation on the transport of impurities in silicon is studied. We use secondary ion mass spectrometry measurements to investigate the depth redistribution of oxygen, carbon, and fluorine during low temperature, 450 °C, isothermal anneals. Their fast migration... (Read more)

Characterization of dominant electron trap in as-grown SiC epilayers has been carried out using deep level transient spectroscopy. Two electron traps E1 and Z₁ at E_c−0.21 and E_c−0.61 are observed, respectively;... (Read more)

The effect of isochronal thermal annealing on Ni/n-GaN Schottky barrier diodes exposed to a total accumulated gamma-ray dose of 21 Mrad(Si) has been investigated using capacitance-voltage (C-V) and current-voltage (I-V) measurements, while capacitance deep-level... (Read more)

A study of deep levels in high purity semi-insulating 4H-SiC has been made using temperature dependent Hall effect (TDH), thermal and optical admittance spectroscopies, and secondary ion mass spectrometry (SIMS). Thermal activation energies from TDH varied from a low of 0.55 eV to a high of... (Read more)

Deep levels in n-type 4H-SiC epilayers have been investigated by deep level transient spectroscopy. The Z_1/2 and EH_6/7 centers are dominant in epilayers grown with low C/Si ratios during chemical vapor deposition. By increasing the C/Si ratio, the... (Read more)

The formation of hydrogen (H)-related complexes and H effects on boron (B) and phosphorus (P) dopants was investigated in B- or P-doped silicon (Si) crystal treated with high concentration of H. The reactivation process of dopant carriers by annealing after hydrogenation was significantly different... (Read more)

The wide-band-gap zinc oxide-based diluted magnetic semiconductors currently attract considerable attention due to their possible use in spintronic devices. In this work, we studied ZnO nanowire samples synthesized on 10×10 mm² a-plane sapphire substrates by high-pressure... (Read more)

Hafnium silicate has a high dielectric constant and is a leading candidate to act as a gate dielectric. The defect energy levels have been calculated. The oxygen vacancy is found to give rise to Si-like levels which lie within the band gap of Si. The vacancy states are very localized and are... (Read more)

The effect of open-core screw dislocations on photoluminescence in n-doped wurtzite GaN epilayer is studied computationally and compared with experimental data. A k•p Hamiltonian calculation domain is set up to contain a dipole of open-core screw dislocations, and its size... (Read more)

In this paper we present a systematic study on the formation of He ion implantation induced nanovoids in Si and how they influence the self-interstitial (Is) supersaturation, thus affecting the diffusion and electrical activation of implanted boron in crystalline silicon. We implanted He ions... (Read more)

We present the results of an electron paramagnetic resonance study of homogeneous single phase Zn_1−xMn_xO thin films with Mn concentrations varying between x=0.07 and x=0.34. Our results show antiferromagnetic (AF) coupling in the entire... (Read more)

The electronic levels of vanadium in semi-insulating 4H- and 6H-SiC have been reinvestigated using temperature dependent Hall effect and resistivity measurements at temperatures up to 1000 K in conjunction with electron paramagnetic resonance (EPR) and optical absorption measurements... (Read more)

Electron spin resonance measurements on 4 and 40 nm thick (HfO₂)_0.6(SiO₂)_0.4 and (HfO₂)_0.4(SiO₂)_0.6 high-κ films on (100)Si wafers detected P_b0 and P_b1... (Read more)

The resistance switching in Pt/Co–O/Pt trilayers has been successfully demonstrated. The trilayers were prepared by radio-frequency magnetron sputtering. The partial pressure of oxygen during sputtering and the post thermal process for the trilayer are crucial to realize the reproducible resistance switching. By adjusting oxygen partial pressure as well as post-annealing temperature and time, large resistance switching was steadily obtainable in both the as deposited and post-annealed Pt/Co–O/Pt trilayers. The resistance switching ratio exceeds 10³, being sufficiently large for the resistance random access memory (RRAM). Co–O is regarded as a very promising oxide for RRAM having compatibilities with the conventional complementary metal–oxide semiconductor process. (Read more)

Electron-irradiated p⁺-n⁻-n⁺ diodes produced from low-doped high-purity Si wafers were found, by deep-level transient spectroscopy (DLTS), to have a prominent defect, labeled E4, with an energy level 0.37 eV below the... (Read more)

We have found evidence of a second acceptor state of the E center in Si_1−xGe_x by using positron annihilation spectroscopy. To achieve this, we studied proton irradiated n-type Si_1−xGe_x with a Ge content... (Read more)

Several radiation defects with effective electron spin S=1 have been observed in synthetic α-quartz, using room-temperature (RT) electron paramagnetic resonance (EPR) spectroscopy. It turns out that these defects had better be considered as biradicals, i.e., pairs of S=1/2... (Read more)

ZnO powder heat treated in NH₃ atmosphere was investigated by electron paramagnetic resonance, photoluminescence, and Raman spectroscopy. We find that the treatment creates Zn interstitials (Zn_i) and complexes of Zn interstitials and nitrogen atoms substituting oxygen... (Read more)

We have studied the small clusters of silicon and carbon interstitials by ab initio supercell calculations in 4H-SiC. We found that silicon interstitials can form stable and electrically active complexes with each other or with a carbon interstitial. Local vibration modes and... (Read more)

We have used positron annihilation spectroscopy to study the introduction and recovery of point defects introduced by 0.45 and 2 MeV electron irradiation at room temperature in n-type GaN. Isochronal annealings were performed up to 1220 K. We observe vacancy defects with specific lifetime... (Read more)

We have performed a comprehensive first-principles investigation of native point defects in ZnO based on density functional theory within the local density approximation (LDA) as well as the LDA+U approach for overcoming the band-gap problem. Oxygen deficiency, manifested in the form of... (Read more)

Interstitial lithium and sodium have been suggested as alternatives to phosphorus to achieve shallow n-type doping of diamond. Experimental results have, however, been contradictory. We report ab initio density functional theory modeling of lithium and sodium in diamond and show that... (Read more)

The capture of an electron by a silicon atom in a defect-free bulk of amorphous silica (a-SiO₂) has been investigated. Ab initio constrained dynamics has been applied to evaluate the energy barrier. The computed energy barrier involved in the mechanism was found to be 0.23 ... (Read more)

The properties of interstitial iron in crystalline silicon and its interactions with hydrogen, shallow acceptors (B, Al, Ga, In, and Tl), and shallow donors (P and As) are calculated from first-principles in periodic supercells. The interactions between the {Fe,B} pair and interstitial hydrogen are... (Read more)

Silicon impurities in diamond lead to the appearance of the well known system of 12 lines around 1.681 eV, thought to arise from the silicon-vacancy complex. This system is produced by various treatments suggestive of other silicon-related centers in the material. In order to elucidate possible... (Read more)

Diamond is a material that shows great promise for particle detection applications. However, under irradiation with energetic particles, many thermally stable defects are created, made up of lattice vacancies, self-interstitials, and complexes with impurities. Relatively distant Frenkel... (Read more)

Vacancy-type defects in as-grown ZnO single crystals have been identified using positron annihilation spectroscopy. The grown-in defects are supposed to be zinc vacancy (V_Zn)-related defects, and can be easily removed by annealing above 600 °C. V_Zn-related... (Read more)

We present a combined experimental and computational study of the (110) cross-sectional surface of Mn δ-doped GaAs samples. We focus our study on three different selected Mn defect configurations not previously studied in detail, namely surface interstitial Mn, isolated and in pairs, and... (Read more)

The electronic structure of Zn_1−xCo_xO (x=0.02, 0.06, and 0.10) diluted magnetic semiconductors is investigated using soft x-ray emission spectroscopy and first-principles calculations. X-ray absorption and emission measurements reveal that most Co... (Read more)

Recent work has suggested that prior determinations of diffusion mechanism and point defect thermodynamics in silicon have been affected by nonequilibrium effects stemming from uncontrolled adsorption-induced suppression of a pathway for defect creation at the surface. Through silicon self-diffusion... (Read more)

Large vacancy clusters, or voids, formed during crystal growth have been reported in Ge. The divacancy is a precursor to such clusters, and is believed to be stable up to 150 or 180 °C. It is also believed to form in Ge irradiated at room temperature where single vacancies are mobile. Density... (Read more)

The intensity and the hyperfine shift of optically polarized NMR (OPNMR) signals of ⁷¹Ga in semi-insulating GaAs have been found to depend on the photon energy and the helicity of light used for optical pumping. Single-crystal GaAs wafers of two different thicknesses, 400 and 175 ... (Read more)

The generally observed higher hole mobility relative to electron mobility in conjugated polymers is explained with the defects and adsorbed molecular oxygen. Adsorption of the extrinsic molecular oxygen leads to that electrons are bound more tightly than holes by the traps in the originally... (Read more)

We use ab initio methods to calculate the magnetic properties of vacancies in a graphitic boron nitride sheet (g-BN). By applying a full spin-polarized description to the system, we demonstrate that the nitrogen vacancy (V_N) or the boron vacancy (V_B)... (Read more)

We have studied, using ab initio density functional theory calculations, substitutional and interstitial Hf impurities in c-Si, for various charge states. Our results indicate that (1) the tetrahedral interstitial defect is energetically more favorable than the substitutional and (2)... (Read more)

We use positron annihilation spectroscopy to study 2 MeV ⁴He⁺-irradiated InN grown by molecular-beam epitaxy and GaN grown by metal-organic chemical-vapor deposition. In GaN, the Ga vacancies act as important compensating centers in the irradiated material, introduced at a... (Read more)

Electron paramagnetic resonance (EPR) studies revealed that vacancies (V_C and V_Si), carbon vacancy-antisite pairs (V_CC_Si) and the divacancy (V_CV_Si) are common defects in high-purity... (Read more)

After low dose electron irradiation, annealing kinetics of divacancy-oxygen (V₂O) and vacancy-oxygen (VO) complexes in carbon-lean n-type magnetic Czochralski (MCZ) and diffusion-oxygenated float-zone (DOFZ) Si samples has been studied in detail. The samples were of n type... (Read more)

Fe-doped ZnO nanocrystals are successfully synthesized and structurally characterized by using x-ray diffraction and transmission electron microscopy. Magnetization measurements on the same system reveal a ferromagnetic to paramagnetic transition temperature above 450 K with a low-temperature... (Read more)

The interactions between edge dislocations and grain boundaries—dislocation pileup, dislocation absorption, and dislocation transmission—are studied by performing quasicontinuum simulations. The 112 asymmetrical tilt grain boundaries with different misorientation angles are used. The... (Read more)

A computationally efficient hybrid Green's function (GF) technique is developed for multiscale modeling of point defects in a trilayer lattice system that links seamlessly the length scales from lattice (subnanometers) to continuum (bulk). The model accounts for the discrete structure of the lattice... (Read more)

Nitrogen substitution of oxygen ions in cubic zirconia was studied theoretically at density functional level. Nitrogen contents of 12.5 and 3.1% were studied with Zr₈O_16−mN₂ and Zr₃₂O_64−mN₂ supercells. For... (Read more)

¹¹⁹Sn NMR studies were carried out for metallic tin confined within synthetic opal and porous glass. Tin was embedded into nanoporous matrices in the melted state under pressure. The Knight shift for liquid confined tin was found to decrease with decreasing pore size. Correlations between... (Read more)

The exact, linear response at steady state is calculated for reacting, but otherwise noninteracting, thermal defects driven by defect creation processes. The theory applies to vacancies and interstitials in the bulk, or to adatoms and advacancies on surface terraces. A wide variety of possible... (Read more)

Understanding radiation-induced defect formation in carbon materials is crucial for nuclear technology and for the manufacturing of nanostructures with desired properties. Using first-principles molecular dynamics, we perform a systematic study of the nonequilibrium processes of radiation damage in... (Read more)

We carry out a comprehensive density-functional study of the vacancy-oxygen (VO) center in germanium using large H-terminated Ge clusters. The importance of a nonlinear core correction to account for the involvement of the 3d electrons in Ge-O bonds is discussed. We calculate the electrical... (Read more)

Intrinsic interstitials in GaAs are known to have a large formation energy that makes their concentration almost negligible in as-grown materials. However, interstitials must be explicitly considered in implanted GaAs where collision cascades, induced by the energetic ions, produce a large amount of... (Read more)

An atomistic simulation of the threading (a+c)-mixed dislocation core in wurtzite GaN has been carried out. Starting from models generated in the framework of continuum elasticity theory, two core configurations are obtained independently by using an empirical potential and a... (Read more)

Grain boundaries are the most inevitable and pronounced structural defects in pentacene films. To study the effect of those structural defects on the electronic state distribution, the energy levels of a hole on molecules at and near the defect have been calculated using a submolecular... (Read more)

Using ab initio total energy density-functional theory calculations, we investigated the electronic, structural, and magnetic properties of manganese-doped germanium nanowires. The nanowires have been constructed along the [110] direction and the dangling bonds on the surface have been... (Read more)

²⁹Si NMR spectra and nuclear spin-lattice relaxation rate measurements in MnSi paramagnetic phase are presented. The experimental results are analyzed in the framework of the self-consistent renormalization theory for spin fluctuations, and detailed estimates of microscopic parameters... (Read more)

Realistic carbon nanotubes (CNTs) contain various structural defects by which the physical and chemical properties of the CNTs are significantly influenced. So, lowering the defect densities is of importance for the potential application of the CNTs. By performing tight-binding molecular dynamics... (Read more)

We study the effect of confinement on the spin polarization of holes bound to Mn acceptors in paramagnetic GaAs:Mn/AlAs multiple quantum wells. It is demonstrated that the polarization of these bound holes is governed by the properties of the host material rather than by quantum confinement. The... (Read more)

The local order around Mn atoms in the Mn-implanted Si samples, with ferromagnetic properties, has been investigated by use of x-ray-absorption spectroscopy techniques. Analysis of both extended x-ray-absorption fine structure and x-ray absorption near-edge structure spectra clearly indicates that... (Read more)

The rearrangement of silicon dangling bonds induced by pulsed laser heating of monohydride-covered Si(001) surfaces has been studied by means of scanning tunneling microscopy (STM). The initial configurations, which were created by laser-induced thermal desorption, consist of isolated pairs of... (Read more)

The effect of HF etching of the silicon oxide shell covering the surface of Si nanocrystals (NCs) on the subsequent room-temperature atmospheric oxidation of Si-NCs has been investigated by means of photoluminescence measurements, Fourier transform infrared spectroscopy, and electron paramagnetic... (Read more)

Silicon carbide nanotubes have a great potential for biological applications. It is of interest to explore the electronic properties of these nanotubes, and how those are modified in the presence of impurities. Hydrogen is a common impurity that can appear during the growth of silicon carbide... (Read more)

A laser-pump, positron-probe technique has been developed for measuring the dynamics of laser-induced paramagnetic centers in porous materials. The basis of the technique is the fact that the annihilation rate of ortho-positronium may increase in the presence of unpaired spins. By using an intense... (Read more)

In this paper we describe the use of electron backscatter diffraction (EBSD) mapping and electron channeling contrast imaging—in the scanning electron microscope—to study tilt, atomic steps and dislocations in epitaxial GaN thin films. We show results from a series of GaN thin films of... (Read more)

Positron lifetime spectroscopy was used to study native vacancy defects in semi-insulating silicon carbide. The material is shown to contain (i) vacancy clusters consisting of four to five missing atoms and (ii) Si-vacancy-related negatively charged defects. The total open volume bound to the... (Read more)

Cathodoluminescence and photoluminescence spectroscopies have been performed on hexagonal boron nitride powders. The combination of these techniques allows us to analyze the two observed luminescence bands. A deep-level UV emission at about 4 eV is attributed to defects or impurities, and a... (Read more)

We calculate the fine structure splitting of the near band edge donor-bound excitons in major cubic semiconductors using an approach inspired by an earlier one that consists in replacing the Morse potential by a Kratzer one, in order to account for the repulsion between the donor and the hole. A... (Read more)

Structural and magnetic properties in Mn-implanted, p-type Si were investigated. High resolution structural analysis techniques such as synchrotron x-ray diffraction revealed the formation of MnSi_1.7 nanoparticles already in the as-implanted samples. Depending on the Mn fluence,... (Read more)

Detailed studies of mechanisms for hydrogen dissociative adsorption and diffusion on pure and nitrogen-doped (8, 0) carbon nanotubes are carried out using the first-principles density functional theory method. (1) For pure carbon nanotubes, we have identified the energetically most favorable... (Read more)

We investigate, through ab initio density-functional theory calculations, the electronic and structural properties of neutral Mn impurities at tetrahedral interstitial and substitutional sites in both Si and Ge layers of a Si/Ge heterostructure. We conclude that substitutional Mn at the Ge... (Read more)

Using spin-polarized density-functional theory with exchange and correlation potential, approximated by both the generalized gradient approximation (GGA) and the GGA+U methods, we show that the coupling between a pair of Cr atoms substituted in GaN nanoholes is ferromagnetic. The interaction between... (Read more)

The optical properties of vertically stacked self-assembled GaN/AlN quantum dots (QD's) grown on Si substrates were studied by means of temporally and spatially resolved cathodoluminescence (CL). An analysis of the CL spectra, thermal activation energies, and measured decay times of the QD... (Read more)

The annealing of damage generated by low-energy ion implantation in polycrystalline silicon (poly-Si) and amorphous silicon (a-Si) is compared. The rate of heat release between implantation temperature and 350–500 °C for Si implanted in both materials and for different ions implanted in... (Read more)

The vibrational lifetimes of a range of H-related defects and interstitial O (O_i) in Si, including isotopic substitutions, are calculated from first principles as a function of temperature. The theoretical approach is explained in detail. The vibrational lifetimes of... (Read more)

Phosphorus is the n-type dopant of choice for diamond, but results in a deep donor level and alternatives are being sought. One possibility is the incorporation of interstitial alkali metal impurities such as Li and Na. We present the results of density-functional calculations used to predict... (Read more)

We present a detailed study of the comparative thermal evolutions of H- and D-related defects in silicon implanted with 2×10¹⁶ H or D/cm², or coimplanted with 0.25×10¹⁶ He/cm² and 0.7×10¹⁶ H/cm², in both orders.... (Read more)

In a recent experiment, Derycke et al. have made the exciting observation that H₂ molecules readily adsorb dissociatively on the c(4×2) but not on the 3×2 surface of SiC(001) at room temperature. To unravel this spectacular reactivity difference, we have investigated a... (Read more)

The structural energetics and diffusion mechanisms of the two most important point defects in rutile TiO₂, the oxygen vacancy (V_O) and the titanium interstitial (Ti_I), are examined using the ab initio pseudopotential total-energy method. The two... (Read more)