Future spintronics devices using quantum dot structures скачать в хорошем качестве

Future spintronics devices using quantum dot structures

[Keio Spintronics Network - Katsumoto Laboratory The University of Tokyo] Institute for Solid State Physics The Katsumoto Laboratory at the University of Tokyo's Institute for Solid State Physics is doing spintronics research, by combining the single-electron effect, which can controls the motion of single electrons in devices, and the quantum interference effect, in which electrons act as probability waves and interfere. The Labs research on quantum effects uses structures called quantum dots. The idea is to control electron spin, by using the Coulomb repulsion between electrons to increase the number of electrons one at a time. One device developed using this technology is a single-electron transistor, which is much smaller than one micron. Q. On scales this small, the single-electron Coulomb force becomes very large, and this can block the next electron. By using the fact that electrons are blocked at one time, and can flow at another time, we can control the number of electrons in here one by one. We can control the number of electrons in the range from zero to about one billion. And were attempting to use this effect in spintronics. Advances in the development of single-electron transistors, which can manipulate spin in units of one electron, will play a major role in computing elements such as CPUs. Also, in research on the quantum interference effect, the Lab is doing experiments on transfer [of what??] to electrical conductors, by investigating the strength of interference using the wavelike characteristics of electrons. If complete spintronics devices can be made by using the results of these experiments, they will be the ultimate in energy efficiency, running on tiny amounts of power. In principle, it will be possible to use a computer for over 100 years on a single battery. Q. Its said that current devices will reach their limit as various things become increasingly small. Of course, theres also the heat generation issue, but there are also various phenomena called quantum fluctuations. Its said that as such phenomena emerge, devices will reach their limit. But conversely, these kinds of phenomena become stronger, so these types of devices will become increasingly usable as quantum fluctuations become worse. Device integration is currently progressing at an astonishing rate, but whereas all devices that run on current principles will become unusable as integration progresses, these kinds of devices will all become usable. In that sense, were running into the walls that exist right now, but were studying devices for the world that exists beyond those walls. In addition to this type of research, we have equipment for molecular beam epitaxy, lithography, and vacuum evaporation in the lab. We do R&D on dilute magnetic semiconductors, at all stages from design to measurement, with the aim of doing further collaborative work on spintronics circuits. Spintronics has the potential to lead to new devices for the future. Professor Katsumoto, whos been involved in this research for many years, explains why spintronics research is so interesting. Q. We often dont get the results we want. We might do an experiment ten times, and succeed once. When we do succeed, it feels great. This sort of thing is really interesting. On the other hand, we dont get disappointed by the nine times we didnt succeed. When we ask why we didnt succeed, new things emerge. Some of them are entirely different from what we designed to occur. Its very interesting to ask why. In a sense, its as if God was laughing at our inexperience, and telling us, Actually, it works like this. Investigating these things is really interesting.