相关论文: Bond angle distribution in amorphous germania and …

Results of X-ray diffraction experiments on solid oxygen at low temperature and at pressures up to 10 GPa are presented.A careful sample preparation and annealing around 240 K allowed to obtain very good diffraction patterns in the…

At a coverage of about 1/3 monolayer, Sn deposited on Ge(111) below 550 forms a metastable (sqrt3 x sqrt3)R30 phase. This phase continuously and reversibly transforms into a (3x3) one, upon cooling below 200 K. The photoemission spectra of…

A theoretical modeling of the oxygen diffusivity in silicon and germanium crystals both at normal and high hydrostatic pressure has been carried out using molecular mechanics, semiempirical and ab initio methods. It was established that the…

The intrinsic nature of glass states and glass transitions at the atomic scale remain a fundamental open question in condensed-matter physics and materials science. By combining femtosecond electron diffraction with time-dependent…

We analyze $^{12}$CO($J$=2-1), $^{13}$CO($J$=2-1), C$^{18}$O ($J$=2-1), and 1.3 mm continuum maps of the $\rho$ Ophiuchi A photo-dissociation region (PDR) obtained with ALMA. Layered structures of the three CO isotopologues with an angular…

Using a custom-built scanning system, we generated maps of birefringence on reflection at $\lambda=1064$~nm from single-crystal GaAs/Al$_{0.92}$Ga$_{0.08}$As Bragg reflectors (henceforth ``AlGaAs coatings''). Ten coatings were bonded to…

Antireflection with broadband and wide angle properties is important for a wide range of applications on photovoltaic cells and display. The SiOx shell layer provides a natural antireflection from air to the Si core absorption layer. In…

With the use of {\em ab initio} based molecular dynamics simulations we study the structural, dynamical and electronic properties of glassy g-GeS$_2$ at room temperature. From the radial distribution function we find nearest neighbor…

Glasses usually represent the lower limit for the thermal conductivity of solids, but a fundamental understanding of lattice heat transport in amorphous materials can provide design rules to beat such a limit. Here we investigate the role…

The structure of Ge$_{22}$Ga$_3$Sb$_{10}$S$_{65}$ and Ge$_{15}$Ga$_{10}$Sb$_{10}$S$_{65}$ glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) measurements at…

The spin-1/2 quantum Heisenberg model is studied in all spatial dimensions d by renormalization-group theory. Strongly asymmetric phase diagrams in temperature and antiferromagnetic bond probability p are obtained in dimensions d \geq 3.…

The structural origin of the first sharp diffraction peak (FSDP) in amorphous silica is studied by analyzing chemical and radial ordering of silicon (Si) and oxygen (O) atoms in binary amorphous networks. The study shows that the chemical…

The medium range order (MRO) in amorphous systems has been linked to complex features such as the dynamic heterogeneity of supercooled liquids or the plastic deformation of glasses. However, the nature of the MRO in these materials has…

For a pendant drop whose contact line is a circle of radius $r_0$, we derive the relation $mg\sin\alpha={\pi\over2}\gamma r_0\,(\cos\theta^{\rm min}-\cos\theta^{\rm max})$ at first order in the Bond number, where $\theta^{\rm min}$ and…

The structural evolution with temperature of pure silica (SiO2), sodium-silicate (5Na2O-95SiO2, 10Na2O-90SiO2 and 25Na2O-75SiO2) and albite (15Na2O-15Al2O3-75SiO2) glasses previously densified from hot compression is monitored with a…

We have constructed microscopic, structurally-relaxed atomistic models of Si/SiO$_2$ superlattices. The structural distortion and oxidation-state characteristics of the interface Si atoms are examined in detail. The role played by the…

Liquid water and vitreous B$_2$O$_3$ are the endpoints of a continuous range of random networks in which hydrogen bonds gradually replace covalent bonds. Previous work has shown that glasses can be obtained by quenching in the range $x \le$…

The electronic structure of Si(110)"16 x 2" double-domain, single-domain and 1 x 1 surfaces have been investigated using spin- and angle-resolved photoemission at sample temperatures of 77 K and 300 K. Angle-resolved photoemission was…

The nuclear scattering at energies well above the Coulomb barrier allows for a fairly sensitive examination of the parameters of the optical potential when the relevant couplings are included into the calculations. In this work we present…

We present a combined experimental and theoretical analysis of the evolution of the near-band gap electronic and optical properties of Si$_{x}$Ge$_{1-x-y}$Sn$_{y}$ alloys lattice-matched to Ge and GaAs substrates. We perform…