Do we follow the money? The drivers of migration across regions in the EU

Most immigration theories tend to highlight that migration follows wealth and economic dynamism, but is this also the case across regions in Europe? The aim of the paper is to investigate whether migrants in Europe indeed follow the money and to contrast this with a variety of potential alternative explanations, including the presence of migrants from a similar origin. The analysis is based on panel data estimations including 133 European regions over a time period of 17 years. Different lag structures have been employed in order to distinguish between short- and long-run effects. The results cast some doubt about the prominence of pecuniary factors as a determinant of cross regional migration in Europe, with little evidence to support the idea that migration follows economic dynamism. Network effects, human capital related-, and ‘territorially embedded' innovation enhancing regional characteristics, by contrast, seem to play a much stronger role than hitherto considered. The study also reveals important differences among EU countries in the factors which determine regional migration.

Field-induced charge transport at the surface of pentacene single crystals: a method to study charge dynamics of 2D electron systems in organic crystals

A method has been developed to inject mobile charges at the surface of organic molecular crystals, and the DC transport of field-induced holes has been measured at the surface of pentacene single crystals. To minimize damage to the soft and fragile surface, the crystals are attached to a pre-fabricated substrate which incorporates a gate dielectric (SiO_2) and four probe pads. The surface mobility of the pentacene crystals ranges from 0.1 to 0.5 cm^2/Vs and is nearly temperature-independent above ~150 K, while it becomes thermally activated at lower temperatures when the induced charges become localized. Ruling out the influence of electric contacts and crystal grain boundaries, the results contribute to the microscopic understanding of trapping and detrapping mechanisms in organic molecular crystals.Comment: 14 pages, 4 figures. Submitted to J. Appl. Phy