Solid-state heterostructures are the cornerstone of modern electronics. To enhance the functionality and performance of integrated circuits, the spectrum of materials used in the heterostructures is being expanded by an increasing number of compounds and elements of the periodic table. While the integration of liquids and solid-liquid interfaces into such systems would allow unique and advanced functional properties and would enable integrated nanoionic circuits, solid-state heterostructures that incorporate liquids have not been considered thus far.
View Article and Find Full Text PDFSrTiO_{3} exhibits a superconducting dome upon doping with Nb, with a maximum critical temperature T_{c}≈0.4 K. Using microwave stripline resonators at frequencies from 2 to 23 GHz and temperatures down to 0.
View Article and Find Full Text PDFThe superconductor at the LaAlO3-SrTiO3 interface provides a model system for the study of two-dimensional superconductivity in the dilute carrier density limit. Here we experimentally address the pairing mechanism in this superconductor. We extract the electron-phonon spectral function from tunneling spectra and conclude, without ruling out contributions of further pairing channels, that electron-phonon mediated pairing is strong enough to account for the superconducting critical temperatures.
View Article and Find Full Text PDFThe physics of the superconducting state in two-dimensional (2D) electron systems is relevant to understanding the high-transition-temperature copper oxide superconductors and for the development of future superconductors based on interface electron systems. But it is not yet understood how fundamental superconducting parameters, such as the spectral density of states, change when these superconducting electron systems are depleted of charge carriers. Here we use tunnel spectroscopy with planar junctions to measure the behaviour of the electronic spectral density of states as a function of carrier density, clarifying this issue experimentally.
View Article and Find Full Text PDFThe vertical distribution of natural radionuclides ((232)Th decay, (238)U decay, (40)K and (210)Pb) was assessed in sediment cores collected from the Amvrakikos Gulf, (Ionian Sea, Western Greece). Two collection stations were selected, the first at the western part of the Gulf near Preveza Strait (13A station) and the other near the centre of the Gulf (13B station). Activity concentrations were measured by means of gamma-ray spectrometry using high-purity germanium (HPGe) detectors installed at two national laboratories.
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