Tekman, E.Çıracı, SalimBaratoff, A.2016-02-082016-02-0819902469-9950http://hdl.handle.net/11693/26223We clarify basic mechanisms for focused field emission of electrons from a point source. The effective potential barrier arising from the lateral confinement of current carrying states is shown to be essential for subband filtering. A hornlike opening at the emission plane further improves the collimation even if the transport is not adiabatic. We predict novel source- and field-dependent resonance effects which can affect the emission characteristics. © 1990 The American Physical Society.EnglishArticle10.1103/PhysRevB.42.9221