Quantized field-electron emission at 300 K in self-assembled arrays of silicon nanowires

Dense ensembles of silicon nanowires were prepared by metal-catalyzed chemical vapor deposition on silicon substrates. Some of these ensembles were doped with phosphorous during growth. The nanowires were characterized using scanning electron microscopy, X-ray diffraction, and mass spectroscopy. Field emission of electrons from these structures was studied at room temperatures in ultra-high vacuum. The measurements were carried out using a parallel-plate diode cell. At high-applied fields, the current–voltage characteristics deviate from the Fowler–Nordheim law and exhibit a step-wise increase in the current with the increasing voltage at 300 K. Possible mechanisms of the observed quantized field emission are discussed.     

Intrinsic spin-Hall effect: topological transitions in two-dimensional systems

Topological transitions are the discontinuous changes of the Berry phase caused by continuous variation of parameters. These transitions can be detected by investigating the spin-Hall effect in two-dimensional electron and hole systems with a spin-obrit interaction when the density of carriers or the structural asymmetry are varied. The discontinuous behavior and the universality features of the spin-Hall conductivity are determined by the topological properties of the spin-orbit field.     

Model completeness for trivial, uncountably categorical theories of Morley rank 1

We show that if T is a trivial uncountably categorical theory of Morley Rank 1 then T is model complete after naming constants for a model.The second author was partially supported by NSF grant DMS-0300080.