No abstract

A measurement of the reduced transition probability for the excitation of the ground state to the first 2 þ state in 104 Sn has been performed using relativistic Coulomb excitation at GSI. 104 Sn is the lightest isotope in the Sn chain for which this quantity has been measured. The result is a key point in the discussion of the evolution of nuclear structure in the proximity of the doubly magic nucleus 100 Sn. The properties of many composite quantum objects that represent building blocks of matter, such as hadrons, atomic nuclei, atoms, and molecules are governed by energy gaps between quantum states which originate in the forces between their fermionic constituents. In the case of atomic nuclei, the energy gaps manifest themselves by the existence of specific stable isotopes. These include, e.g., the double shell-closure nuclei 4 He, 16 O,40;48 Ca, and 208 Pb, which are particularly robust against particle separation and intrinsic excitation. The -unstable isotopes 56 Ni, 78 Ni, and 100;132 Sn are also expected to correspond to double shell closures. However, data for 78 Ni and 100 Sn are scarce due to their exotic neutron-to-proton ratios. Therefore, there is considerable interest in finding more proof for the magicity of these isotopes. In addition, the single particle energies relative to 100 Sn are largely unknown experimentally. Data are limited to the energy splitting between the two lowest-energy orbitals [1,2] while extrapolations from nearby nuclei are available with a typical uncertainty of a few hundred keV for the orbitals of higher energy [3]. Since 100 Sn is predicted to be a doubly magic nucleus, it would provide an approximately inert core on top of which simple excitations can be formed by adding few particles or holes. For this reason, it presents an ideal testing ground for fundamental nuclear models. Another cause for increased interest in nuclear structure in this region comes from the rp process of nuclear synthesis [4]. It has been concluded recently that this reaction sequence comes to an end near 100 Sn [4]. In addition, 100 Sn itself is expected to be the heaviest self-conjugate PRL 110,

III-V nanowire (NW) transistors are an emerging technology with the prospect of high performance and low power dissipation. Performance evaluations of these devices, however, have focused mostly on the intrinsic properties of the NW, excluding any parasitic elements. In this paper, a III-V NW transistor architecture is investigated, based on a NW array with a realistic footprint. Based on scaling rules for the structural parameters, 3-D representations of the transistor are generated, and the parasitic capacitances are calculated. A complete optimization of the structure is performed based on the RF performance metrics f T and f max , employing intrinsic transistor data combined with calculated parasitic capacitances and resistances. The result is a roadmap of optimized transistor structures for a set of technology nodes, with gate lengths down to the 10-nm-length scale. For each technology node, the performance is predicted, promising operation in the terahertz regime. The resulting roadmap has implications as a reference both for benchmarking and for device fabrication.