Thermal stability and nitrogen redistribution in the〈Si〉/Ti/W–N/Al metallization scheme

Backscattering spectrometry, Auger electron spectroscopy, and x‐ray diffraction have been used to monitor the thin‐film reactions and nitrogen redistribution in the 〈Si〉/Ti/W–N/Al metallization system. It is found that nitrogen in the W–N layer redistributes into Ti after annealing at temperatures above 500 °C. As a consequence of this redistribution of nitrogen, a significant amount of interdiffusion between Al and the underlayers is observed after annealing at 550 °C. This result contrasts markedly with that for the 〈Si〉/W–N/Al system, where no interdiffusion can be detected after the same thermal treatment. We attribute this redistribution of nitrogen to the stronger affinity of Ti for nitrogen than W. If the Ti layer is replaced by a sputtered TiSi_(2.3) film, no redistribution of nitrogen or reactions can be detected after annealing at 550 °C for 30 min

Ways of seeing : using filmaking to engage students with communities

Foucault referred to the authoritative ‘gaze’ that can objectify the users of public services and which continues to promote heroic narratives in many areas of professional practice by casting them in a passive role. In the UK, there has been a distinctive and growing discourse about the use and abuse of embedded ‘welfare’ system and within key professions there has been a number of ethical dilemmas and barriers in the quest for community engagement. Working within austerity and tight eligibility criteria has to some extent reinforced individualised pathologies about the causes of social problems and their potential solutions. Generating and exploring counterdiscourses which promote alternative and more challenging perspectives at an early stage in professional education is crucial to encourage students to think more actively about forging partnerships and co-production. This paper shares our experiences of using filmmaking with first year students on the BA (Hons) Social Work where the process of reaching out to communities through a different medium builds in opportunities for students to be more active and open in their search for approaches and interventions which build on the strengths of communities. Students work in small groups to investigate an everyday issue in the community and alongside a range of suggested community project work, generate a short 3-5 minute film which represents different ways of seeing and capturing a range of perspectives on their selected issues. This co-learning approach is also supported by a team of tutors; a service user and graduate student who model the skills required as well as provide peer feedback for students to reflect upon, using double loops of learning experiences. Our presentation will draw on some of the students evaluation which documents the value of such experiential learning and some of the achievements and challenges in its first year including demonstration of one of the student group film

Nonequilibrium-induced metal-superconductor quantum phase transition in graphene

We study the effects of dissipation and time-independent nonequilibrium drive on an open superconducting graphene. In particular, we investigate how dissipation and nonequilibrium effects modify the semi-metal-BCS quantum phase transition that occurs at half-filling in equilibrium graphene with attractive interactions. Our system consists of a graphene sheet sandwiched by two semi-infinite three-dimensional Fermi liquid reservoirs, which act both as a particle pump/sink and a source of decoherence. A steady-state charge current is established in the system by equilibrating the two reservoirs at different, but constant, chemical potentials. The nonequilibrium BCS superconductivity in graphene is formulated using the Keldysh path integral formalism, and we obtain generalized gap and number density equations valid for both zero and finite voltages. The behaviour of the gap is discussed as a function of both attractive interaction strength and electron densities for various graphene-reservoir couplings and voltages. We discuss how tracing out the dissipative environment (with or without voltage) leads to decoherence of Cooper pairs in the graphene sheet, hence to a general suppression of the gap order parameter at all densities. For weak enough attractive interactions we show that the gap vanishes even for electron densities away from half-filling, and illustrate the possibility of a dissipation-induced metal-superconductor quantum phase transition. We find that the application of small voltages does not alter the essential features of the gap as compared to the case when the system is subject to dissipation alone (i.e. zero voltage).Comment: 13 pages, 8 figure

Open String Tachyon in Supergravity Solution

We study the tachyon condensation of the D-\bar{D}-brane system with a constant tachyon vev in the context of classical solutions of the Type II supergravity. We find that the general solution with the symmetry ISO(1,p)xSO(9-p) (the three-parameter solution) includes the extremal black p-brane solution as an appropriate limit of the solution with fixing one of the three parameters (c_1). Furthermore, we compare the long distance behavior of the solution with the massless modes of the closed strings from the boundary state of the D-\bar{D}-brane system with a constant tachyon vev. We find that we must fix c_1 to zero and the only two parameters are needed to express the tachyon condensation of the D\={D}-brane system. This means that the parameter $c_1$ does not correspond to the tachyon vev of the D\={D}-brane system.Comment: 20 pages, no figures, LaTeX2e, typos corrected, references added and more general result presente

Simultaneous Optical Model Analyses of Elastic Scattering, Breakup, and Fusion Cross Section Data for the 6^{6}He + 209^{209}Bi System at Near-Coulomb-Barrier Energies

Based on an approach recently proposed by us, simultaneous $\chi^{2}$-analyses are performed for elastic scattering, direct reaction (DR) and fusion cross sections data for the $^{6}$He+$^{209}$Bi system at near-Coulomb-barrier energies to determine the parameters of the polarization potential consisting of DR and fusion parts. We show that the data are well reproduced by the resultant potential, which also satisfies the proper dispersion relation. A discussion is given of the nature of the threshold anomaly seen in the potential