Current control in soft-wall electron billiards: Energy-persistent scattering in the deep quantum regime

Abstract

In this chapter we use ‘soft-wall’ boundary confinement, that is, a potential profile with finite slope, to induce charge current controllability in a two-terminal transport setup. In particular, the isolation of energetically persistent scattering pathways from the resonant manifold of an elongated electron billiard in the deep quantum regime is demonstrated. This in turn enables efficient conductance switching at varying temperature and Fermi velocity, using a weak magnetic field. The effect relies on the interplay between the elongated soft-wall confinement and magnetic focusing, which together rescale the scattering pathways and decouple quasi-bound states from the attached leads. The mechanism proves robust against billiard shape variations and qualifies as a nanoelectronic current control element.