Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism

This article reviews the application of the non-equilibrium Green's function formalism to the simulation of novel photovoltaic devices utilizing quantum confinement effects in low dimensional absorber structures. It covers well-known aspects of the fundamental NEGF theory for a system of interacting electrons, photons and phonons with relevance for the simulation of optoelectronic devices and introduces at the same time new approaches to the theoretical description of the elementary processes of photovoltaic device operation, such as photogeneration via coherent excitonic absorption, phonon-mediated indirect optical transitions or non-radiative recombination via defect states. While the description of the theoretical framework is kept as general as possible, two specific prototypical quantum photovoltaic devices, a single quantum well photodiode and a silicon-oxide based superlattice absorber, are used to illustrated the kind of unique insight that numerical simulations based on the theory are able to provide.Comment: 20 pages, 10 figures; invited review pape

Interest groups in multiple streams:specifying their involvement in the framework

Although interests inhabit a central place in the multiple streams framework (MSF), interest groups have played only a minor role in theoretical and empirical studies until now. In Kingdon’s original conception, organized interests are a key variable in the politics stream. Revisiting Kingdon’s concept with a particular focus on interest groups and their activities—in different streams and at various levels—in the policy process, we take this argument further. In particular, we argue that specifying groups’ roles in other streams adds value to the explanatory power of the framework. To do this, we look at how interest groups affect problems, policies, and politics. The influence of interest groups within the streams is explained by linking the MSF with literature on interest intermediation. We show that depending on the number of conditions and their activity level, interest groups can be involved in all three streams. We illustrate this in case studies reviewing labor market policies in Germany and chemicals regulation at the European level

Model International Mobility Convention

While people are as mobile as they ever were in our globalized world, the movement of people across borders lacks global regulation. This leaves many refugees in protracted displacement and many migrants unprotected in irregular and dire situations. Meanwhile, some states have become concerned that their borders have become irrelevant. International mobility—the movement of individuals across borders for any length of time as visitors, students, tourists, labor migrants, entrepreneurs, long-term residents, asylum seekers, or refugees—has no common definition or legal framework. To address this key gap in international law, and the growing gaps in protection and responsibility that are leaving people vulnerable, the "Model International Mobility Convention" proposes a framework for mobility with the goals of reaffirming the existing rights afforded to mobile people (and the corresponding rights and responsibilities of states) as well as expanding those basic rights where warranted. In 213 articles divided over eight chapters, the Convention establishes both the minimum rights afforded to all people who cross state borders as visitors, and the special rights afforded to tourists, students, migrant workers, investors and residents, forced migrants, refugees, migrant victims of trafficking and migrants caught in countries in crisis. Some of these categories are covered by existing international legal regimes. However, in this Convention these groups are for the first time brought together under a single framework. An essential feature of the Convention is that it is cumulative. This means, for the most part, that the chapters build on and add rights to the set of rights afforded to categories of migrants covered by earlier chapters. The Convention contains not only provisions that afford rights to migrants and, to a lesser extent, States (such as the right to decide who can enter and remain in their territory). It also articulates the responsibilities of migrants vis-à-vis States and the rights and responsibilities of different institutions that do not directly respond to a right held by migrants

Interest Groups, NGOs or Civil Society Organisations? The Framing of Non-State Actors in the EU

Scholars have used varying terminology for describing non-state entities seeking to influence public policy or work with the EU’s institutions. This paper argues that the use of this terminology is not and should not be random, as different ‘frames’ come with different normative visions about the role(s) of these entities in EU democracy. A novel bibliometric analysis of 780 academic publications between 1992 and 2020 reveals that three frames stand out: The interest group frame, the NGO frame, as well as the civil society organisation frame; a number of publications also use multiple frames. This article reveals the specific democratic visions contained in these frames, including a pluralist view for interest groups; a governance view for NGOs as ‘third sector’ organisations, and participatory and deliberative democracy contributions for civil society organisations. The use of these frames has dynamically changed over time, with ‘interest groups’ on the rise. The results demonstrate the shifting focus of studies on non-state actors in the EU and consolidation within the sub-field; the original visions of European policy-makers emerging from the 2001 White Paper on governance may only partially come true

Exchange Bias in Fe@Cr Core–Shell Nanoparticles

We have used X-ray magnetic circular dichroism and magnetometry to study isolated Fe@Cr core−shell nanoparticles with an Fe core diameter of 2.7 nm (850 atoms) and a Cr shell thickness varying between 1 and 2 monolayers. The addition of Cr shells significantly reduces the spin moment but does not change the orbital moment. At least two Cr atomic layers are required to stabilize a ferromagnetic/antiferromagnetic interface and generate the associated exchange bias and increase in coercivity