H\"older Regularity For Integro-Differential Equations With Nonlinear Directional Dependence

We prove H\"older regularity results for a class of nonlinear elliptic integro-differential operators with integration kernels whose ellipticity bounds are strongly directionally dependent. These results extend those in [9] and are also uniform as the order of operators approaches 2

Diffuse LEED intensities of disordered crystal surfaces : III. LEED investigation of the disordered (110) surface of gold

The LEED pattern of clean (101) surfaces of Au show a characteristic (1 × 2) superstructure. The diffuseness of reflections in the reciprocal [010] direction is caused by one-dimensional disorder of chains, strictly ordered into spatial [10 ] direction. There is a transition from this disordered superstructure to the normal (1 × 1) structure at 420 + 15°C. The angular profiles of the and (01) beam are measured at various temperatures and with constant energy and angles of incidence of the primary beam. The beam profiles are deconvoluted approximately with the instrument response function

Consistency of WIMP Dark Matter as radiative neutrino mass messenger

The scotogenic scenario provides an attractive approach to both Dark Matter and neutrino mass generation, in which the same symmetry that stabilises Dark Matter also ensures the radiative seesaw origin of neutrino mass. However the simplest scenario may suffer from inconsistencies arising from the spontaneous breaking of the underlying $\mathbb{Z}_2$ symmetry. Here we show that the singlet-triplet extension of the simplest model naturally avoids this problem due to the presence of scalar triplets neutral under the $\mathbb{Z}_2$ which affect the evolution of the couplings in the scalar sector. The scenario offers good prospects for direct WIMP Dark Matter detection through the nuclear recoil method.Comment: 16 pages, 7 figure

Multilayer distortion in the reconstructed (110) surface of Au

A new LEED intensity analysis of the reconstructed Au(110)-(1×2) surface results in a modification of the missing row model with considerable distortions which are at least three layers deep. The top layer spacing is contracted by about 20%, the second layer exhibits a lateral pairing displacement of 0.07 Å and the third layer is buckled by 0.24 Å. Distortions in deeper layers seem to be probable but have not been considered in this analysis. The inter-atomic distances in the distorted surface region show both an expansion and a contraction compared to the bulk value and range from 5% contraction to about 4% expansion

Scanning Photo-Induced Impedance Microscopy - Resolution studies and polymer characterization

Scanning Photo-Induced Impedance Microscopy (SPIM) is an impedance imaging technique that is based on photocurrent measurements at field-effect structures. The material under investigation is deposited onto a semiconductor-insulator substrate. A thin metal film or an electrolyte solution with an immersed electrode serves as the gate contact. A modulated light beam focused into the space charge region of the semiconductor produces a photocurrent, which is directly related to the local impedance of the material. The absolute impedance of a polymer film can be measured by calibrating photocurrents using a known impedance in series with the sample. Depending on the wavelength of light used, charge carriers are not only generated in the focus but also throughout the bulk of the semiconductor. This can have adverse effects on the lateral resolution. Two-photon experiments were carried out to confine charge carrier generation to the spacecharge layer. The lateral resolution of SPIM is also limited by the lateral diffusion of charge carriers in the semiconductor. This problem can be solved by using thin silicon layers as semiconductor substrates. A resolution of better than 1 mu m was achieved using silicon on sapphire (SOS) substrates with a I l.Lm thick silicon layer

A leed analysis of the (2×1)H-Ni(110) structure

A monolayer of H atoms adsorbed on Ni(110) below 180 K forms a (2×1) structure. The unit cell exhibits a glide symmetry plane and contains two adsorbed atoms. Based on a quantitative comparison between experimental and calculated LEED I/V spectra using standard R-factors the following structure was derived: On the clean Ni(110) surface the separation between the first two atomic layers, d12, is contracted by 8.5%±1.5% with respect to the bulk value; those between the second and third and the third and fourth layer, d23 and d34, are expanded by 3.5%±1.5% and 1%±1.5%, respectively—in agreement with recent other results. In the presence of the H adlayer the contraction of d12 is reduced to 4.5%±1.5%, while the expansion of d23 is not affected within the limits of accuracy. The third interlayer spacing d34 returns to its bulk value. The H atoms occupy threefold-coordinated sites formed by two Ni atoms from the first layer and one Ni atom from the second layer which confirms previous more qualitative conclusions based on He diffraction and vibrational spectroscopy. The bond lengths between H and its neighbouring Ni atoms were determined to be equal, namely 1.72±0.1 Å