The size-induced metal-insulator transition and related electron interference phenomena in modern microelectronics

Abstract

The localization of conduction electrons in defect-induced or size-induced confinements is a universal effect of potential barriers on the wave nature of electrons. Both elastic and inelastic scattering disturb the coherence of electron waves. When the distance between potential barriers approaches the coherence length, classical conduction breaks down. Instead, an electron standing wave pattern is built up analogous to that of electromagnetic waves in a heterogeneous waveguide. The decay of the quasi-static Drude conductivity with crystal volumein well-separated mesoscopic conductors represents an experimental manifestation of electron interference effects. This size-induced metal-insulator transition (SIMIT) is in agreement with the quantum model Gor'kov and Eliashberg developed some 25 years ago. The SIMIT indicates the operational size limit for microelectronic devices based on particle-like transport. Future minuscule devices will exploit the electron wave nature. The variety of these novel designs comprises heterostructures and size-induced potential barriers. Here we introduce a new class of devices whose energy gap is simply taylored by structuring their cross section.