Spin transmission control in helical magnetic fields

We calculate spin transport in two-dimensional waveguides in the presence of spatially modulated Zeeman-split energy bands. We show that in a regime where the spin evolution is predominantly adiabatic the spin backscattering rate can be tuned via diabatic Landau-Zener transitions between the spin-split bands [C. Betthausen et. al., Science 337, 324 (2012)]. This mechanism is tolerant against spin-independent scattering processes. Completely spin-polarized systems show full spin backscattering, and thus current switching. In partially spin-polarized systems a spatial sequence of Landau-Zener transition points enhances the resistance modulation via reoccupation of backscattered spin-polarized transport modes. We discuss a possible application as a spin transistor.Comment: Theory related to the adiabatic spin transistor concept (C. Betthausen et al., Science 337, 324 (2012), DOI: 10.1126/science.1221350

Narrowband organic photodetectors-towards miniaturized, spectroscopic sensing

Omnipresent quality monitoring in food products, blood-oxygen measurement in lightweight conformal wrist bands, or data-driven automated industrial production: Innovation in many fields is being empowered by sensor technology. Specifically, organic photodetectors (OPDs) promise great advances due to their beneficial properties and low-cost production. Recent research has led to rapid improvement in all performance parameters of OPDs, which are now on-par or better than their inorganic counterparts, such as silicon or indium gallium arsenide photodetectors, in several aspects. In particular, it is possible to directly design OPDs for specific wavelengths. This makes expensive and bulky optical filters obsolete and allows for miniature detector devices. In this review, recent progress of such narrowband OPDs is systematically summarized covering all aspects from narrow-photo-absorbing materials to device architecture engineering. The recent challenges for narrowband OPDs, like achieving high responsivity, low dark current, high response speed, and good dynamic range are carefully addressed. Finally, application demonstrations covering broadband and narrowband OPDs are discussed. Importantly, several exciting research perspectives, which will stimulate further research on organic-semiconductor-based photodetectors, are pointed out at the very end of this review

3D-Hydrogen Analysis of Ferromagnetic Microstructures in Proton Irradiated Graphite

Recently, magnetic order in highly oriented pyrolytic graphite (HOPG) induced by proton broad- and microbeam irradiation was discovered. Theoretical models propose that hydrogen could play a major role in the magnetism mechanism. We analysed the hydrogen distribution of pristine as well as irradiated HOPG samples, which were implanted to micrometer-sized spots as well as extended areas with various doses of 2.25 MeV protons at the Leipzig microprobe LIPSION. For this we used the sensitive 3D hydrogen microscopy system at the Munich microprobe SNAKE. The background hydrogen level in pristine HOPG is determined to be less than 0.3 at-ppm. About 4.8e15 H-atoms/cm^2 are observed in the near-surface region (4 um depth resolution). The depth profiles of the implants show hydrogen located within a confined peak at the end of range, in agreement with SRIM Monte Carlo simulations, and no evidence of diffusion broadening along the c-axis. At sample with microspots, up to 40 at-% of the implanted hydrogen is not detected, providing support for lateral hydrogen diffusion.Comment: accepted for publication in Nucl. Instr. and Met

Growth kinetics, structure, and morphology of para-quaterphenyl thin films on gold(111)

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What we talk about when we talk about "global mindset": managerial cognition in multinational corporations

Recent developments in the global economy and in multinational corporations have placed significant emphasis on the cognitive orientations of managers, giving rise to a number of concepts such as “global mindset” that are presumed to be associated with the effective management of multinational corporations (MNCs). This paper reviews the literature on global mindset and clarifies some of the conceptual confusion surrounding the construct. We identify common themes across writers, suggesting that the majority of studies fall into one of three research perspectives: cultural, strategic, and multidimensional. We also identify two constructs from the social sciences that underlie the perspectives found in the literature: cosmopolitanism and cognitive complexity and use these two constructs to develop an integrative theoretical framework of global mindset. We then provide a critical assessment of the field of global mindset and suggest directions for future theoretical and empirical research

Bourdieu's non-material forms of capital:Implications for start-up policy

The role of Bourdieu’s non-material forms of capital (cultural, social and symbolic) in the entrepreneurial process has received little dedicated research attention. Similarly, the link between occupationally distinct entrepreneurship and accumulation of non-material capitals is understudied. Addressing this, we examine the non-material capitals of different nascent entrepreneurs by occupational classification who participated on two enterprise-training programmes funded by the 1997-2010 Labour Government; each with considerably different foci. Findings demonstrate that professional and higher technician entrepreneurs possess valuable non-material capitals, in contrast to non-professional entrepreneurs. Against the backdrop of recent business enterprise policy, findings suggest that policy-makers should prioritise focused support that nurtures the valuable, productive non-material capitals of professional and higher technician entrepreneurs. Furthermore, initiatives should be tailored to improve the less distinguished non-material capitals of non-professional entrepreneurs