Josephson Junctions defined by a Nano-Plough

We define superconducting constrictions by ploughing a deposited Aluminum film with a scanning probe microscope. The microscope tip is modified by electron beam deposition to form a nano-plough of diamond-like hardness, what allows the definition of highly transparent Josephson junctions. Additionally a dc-SQUID is fabricated to verify appropriate functioning of the junctions. The devices are easily integrated in mesoscopic devices as local radiation sources and can be used as tunable on-chip millimeter wave sources

Microwave spectroscopy on a double quantum dot with an on-chip Josephson oscillator

We present measurements on microwave spectroscopy on a double quantum dot with an on-chip microwave source. The quantum dots are realized in the two-dimensional electron gas of an AlGaAs/GaAs heterostructure and are weakly coupled in series by a tunnelling barrier forming an 'ionic' molecular state. We employ a Josephson oscillator formed by a long Nb/Al-AlO$_x$/Nb junction as a microwave source. We find photon-assisted tunnelling sidebands induced by the Josephson oscillator, and compare the results with those obtained using an externally operated microwave source.Comment: 6 pages, 4 figure

Effects of nonorthogonality in the time-dependent current through tunnel junctions

A theoretical technique which allows to include contributions from non-orthogonality of the electron states in the leads connected to a tunneling junction is derived. The theory is applied to a single barrier tunneling structure and a simple expression for the time-dependent tunneling current is derived showing explicit dependence of the overlap. The overlap proves to be necessary for a better quantitative description of the tunneling current, and our theory reproduces experimental results substantially better compared to standard approaches.Comment: 4 pages, 1 table, 1 figur

Phonon-plasmon coupling in Si doped GaN nanowires

The vibrational properties of silicon doped GaN nanowires with diameters comprised between 40 and 100 nm are studied by Raman spectroscopy through excitation with two different wavelengths: 532 and 405 nm. Excitation at 532 nm does not allow the observation of the coupled phonon-plasmon upper mode for the intentionally doped samples. Yet, excitation at 405 nm results in the appearance of a narrow peak at frequencies close to that of the uncoupled A1(LO) mode for all samples. This behavior points to phonon-plasmon scattering mediated by large phonon wave-vector in these thin and highly doped nanowires

Spin polarization of the L-gap surface states on Au(111)

The electron spin polarization (ESP) of the L-gap surface states on Au(111) is investigated theoretically by means of first-principles electronic-structure and photoemission calculations. The surface states show a large spin-orbit induced in-plane ESP which is perpendicular to the in-plane wavevector, in close analogy to a two-dimensional electron gas with Rashba spin-orbit interaction. The surface corrugation leads to a small ESP component normal to the surface, being not reported so far. The surface-states ESP can be probed qualitatively and quantitatively by spin- and angle-resolved photoelectron spectroscopy, provided that the initial-state ESP is retained in the photoemission process and not obscured by spin-orbit induced polarization effects. Relativistic photoemission calculations provide detailed information on what photoemission set-ups allow to conclude from the photoelectron ESP on that of the surface states.Comment: 22 pages with 8 figure

Investigation of contact deformation and wear characteristics of discrete track recording media

The even semester 2014/2015 Technical Information Engineering University of Semarang (USM) has been running the Competency Based Curriculum (CBC) in the management of learning. Conversions that occur in some subjects at an increase in scheduled meetings in the classroom or in the laboratory. Computer Networks is one of the subjects who experienced a conversion. In the curriculum in 2008, Computer Networking has a number of credits 3. From the 2 credits 3 credits are for credits 1 credits for theory and practical credits. While at the CBC in 2013, Computer Networking has 4 credits, with details of 2 credits 2 credits theory and practicum. As lecture and instructor Computer Network, researchers interested in studying the effect of applying the CBC in 2013 in the subje ct of Computer Network. Does the addition of meeting practical and theoretical material renewal in accordance with the expected competencies?. Researchers tried applying the CBC in 2013 by conducting action research. Implementation of the research was conducted during an ongoing lecture that even semester 2015/2016. The results of the study during the first half of researchers will compare with the achievements that never existed when the old curriculum still in use. The goals of this research is, subjects in the Computer Network has always been one of the subjects that the content of the material and its application in the lab was able to follow the needs of the workforc

Spin polarized photoelectrons with unpolarized light in normal emission from Pt(110)

Irmer N, Frentzen F, Schmiedeskamp B, Heinzmann U. Spin polarized photoelectrons with unpolarized light in normal emission from Pt(110). Surface Science. 1994;307-309(2):1114-1117.The normally emitted photoelectrons of the reconstructed (1 x 2) surface of Pt(110) caused by off-normally incoming, unpolarized light are spin polarized. Measurements have been performed with the light of a gas discharge tube and spin polarization of up to 20% has been found for the spin polarization perpendicular to the reaction plane, defined by the momenta of incoming photon and outgoing electron beam. The polarization depends significantly on a rotation of the crystal about the surface normal. The experimental data are in good agreement with theoretical calculations of Feder's group [1] based upon the theory describing the photoemission in the one-step model

Teaching and Assessing Critical Thinking, Nuts and Bolts 1 TEACHING AND ASSESSING CRITICAL THINKING: THE INTERACTION OF STUDENT APPROACHES TO LEARNING AND TEACHING APPROACHES

Abstract This study explored the relationship among student approaches to learning and teaching methods on critical thinking in two business units. Key findings included differences in critical thinking scores between student approaches to learning and some evidence of an interaction between student approaches to learning and critical thinking teach method (immersion vs. infusio

Grain boundary diffusion and segregation of Cr in Ni Σ11(1̄13)[110] bicrystals: Decoding the role of grain boundary defects

Grain boundary diffusion of Cr in a near Σ11(1̄13)[110] Ni bicrystal is measured over a temperature interval between 503 K and 1203 K using the radiotracer technique. The grain boundary diffusion coefficients, Dgb, and the triple products, P=s⋅δ⋅Dgb, are determined in the C- and B-type kinetics regimes, respectively, with s being the segregation factor and δ the grain boundary width. Opposite to expectations, two distinct contributions to short-circuit diffusion along the nominally single interface are distinguished and related to the existence of two macroscopic facets with distinct grain boundary inclinations and, as a result, distinct structures. The experimental results indicate that the segregation factor of Cr in Ni is about unity, which is fully supported by ab initio calculations. Using classical atomistic simulations, Ni grain boundary self-diffusion coefficients are calculated for the symmetric and asymmetric facets. The computational simulations reveal accelerated self-diffusion kinetics along the asymmetric facet, attributing this phenomenon to the presence of disconnection-like defects. This elucidates the experimentally observed diffusion dynamics of chromium atoms, thereby corroborating the heterogeneous mechanisms governing atomic migration across distinct facets

Early Pastoral Economies and Herding Transitions in Eastern Eurasia

While classic models for the emergence of pastoral groups in Inner Asia describe mounted, horse-borne herders sweeping across the Eurasian Steppes during the Early or Middle Bronze Age (ca. 3000–1500 BCE), the actual economic basis of many early pastoral societies in the region is poorly characterized. In this paper, we use collagen mass fingerprinting and ancient DNA analysis of some of the first stratified and directly dated archaeofaunal assemblages from Mongolia’s early pastoral cultures to undertake species identifications of this rare and highly fragmented material. Our results provide evidence for livestock-based, herding subsistence in Mongolia during the late 3rd and early 2nd millennia BCE. We observe no evidence for dietary exploitation of horses prior to the late Bronze Age, ca. 1200 BCE – at which point horses come to dominate ritual assemblages, play a key role in pastoral diets, and greatly influence pastoral mobility. In combination with the broader archaeofaunal record of Inner Asia, our analysis supports models for widespread changes in herding ecology linked to the innovation of horseback riding in Central Asia in the final 2nd millennium BCE. Such a framework can explain key broad-scale patterns in the movement of people, ideas, and material culture in Eurasian prehistory