  Resistance switching random access memory (ReRAM), with the ability to
repeatedly modulate electrical resistance, has been highlighted as a feasible
high-density memory with the potential to replace negative-AND (NAND) flash
memory. Such resistance modulation usually involves ion migration and filament
formation, which usually lead to relatively low device reliability and yield.
Resistance switching can also come from an entirely electronic origin, as in
nanometallic memory, by electron trapping and detrapping. Recent research has
revealed additional merits of its mechanism, which entails smart, atomic-sized
floating gates that can be easily engineered in amorphous Si, oxides, and
nitrides. This article addresses the basic ideas of nanometallic ReRAM, which
may also be a contender for analogue computing and non-von Neumann-type
computation.
