Energy quantization in solution-processed layers of indium oxide and their application in resonant tunneling diodes

\u3cp\u3eThe formation of quantized energy states in ultrathin layers of indium oxide (In\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e) grown via spin coating and thermally annealed at 200°C in air is studied. Optical absorption measurements reveal a characteristic widening of the optical band gap with reducing In\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e layer thickness from ≈43 to ≈3 nm in agreement with theoretical predictions for an infinite quantum well. Through sequential deposition of In\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e and gallium oxide (Ga\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e) layers, superlattice-like structures with controlled dimensionality and spatially varying conduction band characteristics are demonstrated. This simple method is then explored for the fabrication of functional double-barrier resonant tunneling diodes. Nanoscale current mapping analysis using conductive atomic force microscopy reveals that resonant tunneling is not uniform but localized in specific regions of the apparent device area. The latter observation is attributed to variation in the layer(s) thickness of the In\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e quantum well and/or the Ga\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e barrier layers. Despite the nonidealities, the tremendous potential of solution-processable oxide semiconductors for the development of quantum effect devices that have so far been demonstrated only via sophisticated growth techniques is demonstrated.\u3c/p\u3

Pedagogical Beliefs and Attitudes toward Information and Communication Technology: A Survey of Teachers of English as a Foreign Language in China

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.Though pedagogical beliefs have been identified as critical factors in the success of technology integration, very few studies have included them in technology-adoption models. The present study revises the Technology Acceptance Model (TAM) by adding teachers’ pedagogical beliefs, and tests the revised model among university-level English as a foreign language (EFL) teachers in China. Specifically, the revised model examines how teachers’ constructivist and/or transmissive pedagogical beliefs influence four key constructs of the TAM: perceived usefulness, perceived ease of use, attitude toward use, and intention to use. Survey data were collected from 202 Chinese EFL teachers and analyzed using path analysis. The revised model showed a good model fit. The results indicated that the sampled teachers’ pedagogical beliefs were more constructivist-oriented than transmissive-oriented, and that the former type of beliefs had a significant positive influence on three of the above-mentioned TAM constructs (perceived usefulness, perceived ease of use, and attitude toward use). Teachers’ transmissive pedagogical beliefs, on the other hand, did not have any significant impact on their attitudes toward information and communication technology (ICT) or their perceptions of its usefulness, though such beliefs did significantly affect their perceptions of how easy ICT was to use. Implications of these findings for teacher education and professional training are discussed

A Spin-Isospin Dependent 3N Scattering Formalism in a 3D Faddeev Scheme

We have introduced a spin-isospin dependent three-dimensional approach for formulation of the three-nucleon scattering. Faddeev equation is expressed in terms of vector Jacobi momenta and spin-isospin quantum numbers of each nucleon. Our formalism is based on connecting the transition amplitude $T$ to momentum-helicity representations of the two-body $t$-matrix and the deuteron wave function. Finally the expressions for nucleon-deuteron elastic scattering and full breakup process amplitudes are presented.Comment: 17 page

A New Treatment of 2N and 3N Bound States in Three Dimensions

The direct treatment of the Faddeev equation for the three-boson system in 3 dimensions is generalized to nucleons. The one Faddeev equation for identical bosons is replaced by a strictly finite set of coupled equations for scalar functions which depend only on 3 variables. The spin-momentum dependence occurring as scalar products in 2N and 3N forces accompanied by scalar functions is supplemented by a corresponding expansion of the Faddeev amplitudes. After removing the spin degrees of freedom by suitable operations only scalar expressions depending on momenta remain. The corresponding steps are performed for the deuteron leading to two coupled equations.Comment: 19 page

Determining replenishment lot size and shipment policy for an extended EPQ model with delivery and quality assurance issues

AbstractThis paper derives the optimal replenishment lot size and shipment policy for an Economic Production Quantity (EPQ) model with multiple deliveries and rework of random defective items. The classic EPQ model assumes a continuous inventory issuing policy for satisfying demand and perfect quality for all items produced. However, in a real life vendor–buyer integrated system, multi-shipment policy is practically used in lieu of continuous issuing policy and generation of defective items is inevitable. It is assumed that the imperfect quality items fall into two groups: the scrap and the rework-able items. Failure in repair exists, hence additional scrap items generated. The finished items can only be delivered to customers if the whole lot is quality assured at the end of rework. Mathematical modeling is used in this study and the long-run average production–inventory-delivery cost function is derived. Convexity of the cost function is proved by using the Hessian matrix equations. The closed-form optimal replenishment lot size and optimal number of shipments that minimize the long-run average costs for such an EPQ model are derived. Special case is examined, and a numerical example is provided to show its practical usage

Three-body scattering in Poincar\'e invariant quantum mechanics

The relativistic three-nucleon problem is formulated by constructing a dynamical unitary representation of the Poincar\'e group on the three-nucleon Hilbert space. Two-body interactions are included that preserve the Poincar\'e symmetry, lead to the same invariant two-body S-matrix as the corresponding non-relativistic problem, and result in a three-body S-matrix satisfying cluster properties. The resulting Faddeev equations are solved by direct integration, without partial waves for both elastic and breakup reactions at laboratory energies up to 2 Gev.Comment: 4 pages - no figures - contribution to the 20-th European Few-Body Conferenc

3N Scattering in a Three-Dimensional Operator Formulation

A recently developed formulation for a direct treatment of the equations for two- and three-nucleon bound states as set of coupled equations of scalar functions depending only on vector momenta is extended to three-nucleon scattering. Starting from the spin-momentum dependence occurring as scalar products in two- and three-nucleon forces together with other scalar functions, we present the Faddeev multiple scattering series in which order by order the spin-degrees can be treated analytically leading to 3D integrations over scalar functions depending on momentum vectors only. Such formulation is especially important in view of awaiting extension of 3N Faddeev calculations to projectile energies above the pion production threshold and applications of chiral perturbation theory 3N forces, which are to be most efficiently treated directly in such three-dimensional formulation without having to expand these forces into a partial wave basis.Comment: 25 pages, 0 figure

Two-gap superconductivity in Ba_1-xK_xFe_2As_2: A complementary study of the magnetic penetration depth by \muSR and ARPES

We investigate the magnetic penetration depth \lambda in superconducting Ba_1-xK_xFe_2As_2 (T_c\simeq32K) with muon-spin rotation (\muSR) and angle-resolved photoemission (ARPES). Using \muSR, we find the penetration-depth anisotropy \gamma_\lambda=\lambda_c/\lambda_{ab} and the second-critical-field anisotropy \gamma_{H_c2} to show an opposite T-evolution below T_c. This dichotomy resembles the situation in the two-gap superconductor MgB_2. A two-gap scenario is also suggested by an inflection point in the in-plane penetration depth \lambda_ab around 7K. The complementarity of \muSR and ARPES allows us to pinpoint the values of the two gaps and to arrive to a remarkable agreement between the two techniques concerning the full T-evolution of \lambda_ab. This provides further support for the described scenario and establishes ARPES as a tool to assess macroscopic properties of the superconducting condensate.Comment: Accepted for publication by Phys. Rev. Let

First Order Relativistic Three-Body Scattering

Relativistic Faddeev equations for three-body scattering at arbitrary energies are formulated in momentum space and in first order in the two-body transition-operator directly solved in terms of momentum vectors without employing a partial wave decomposition. Relativistic invariance is incorporated within the framework of Poincare invariant quantum mechanics, and presented in some detail. Based on a Malfliet-Tjon type interaction, observables for elastic and break-up scattering are calculated up to projectile energies of 1 GeV. The influence of kinematic and dynamic relativistic effects on those observables is systematically studied. Approximations to the two-body interaction embedded in the three-particle space are compared to the exact treatment.Comment: 26 pages, 13 figure

Poincare Invariant Three-Body Scattering

Relativistic Faddeev equations for three-body scattering are solved at arbitrary energies in terms of momentum vectors without employing a partial wave decomposition. Relativistic invariance is incorporated withing the framework of Poincar\'e invariant quantum mechanics. Based on a Malfliet-Tjon interaction, observables for elastic and breakup scattering are calculated and compared to non-relativistic ones.Comment: 4 pages, 2 figures. Proceedings of the workshop "Critical Stability of Few-Body Quantum Systems" 200