Spontaneous spin polarization of electrons in two-dimensional arrays of quantum dots: Possibilities for a novel quantum coupled computer architecture

摘要

The idea of using the spin of an electron to encode binary bit information was proposed by Feynman in the 1960s. In this paper the authors show that an array of quantum dots, each containing a single electron, can realize a quantum coupled computer architecture where each electron acts as a bistable logic device and its spin encodes its logic state. Such an architecture has many advantages such as (1) the absence of physical interconnects between devices, (b) ultrafast switching times (spin flip times) of (approximately)1 picosecond for individual devices, (c) extremely high bit density approaching 10 Terabits/cm(sup 2), (4) non-volatile memory, (5) robustness and possible room temperature operation with very high noise margin and reliability, (6) a very low power delay product for switching between logic levels, and (7) a very small power dissipation of a few tens of nanowatts per switching event. In spite of the above advantages, the technology also has some serious drawbacks in that the fan-out of individual logic devices may be small, wiring crossover is very problematic and the devices themselves have no inherent gain so that isolation between input and output is a problem. The authors discuss these problems, and where possible, offer plausible solutions.