Some time ago, the publication Communications Physics published a scientific article “Harnessing ferroelectric domains for negative capacitance”, the authors of which were Russian physicists from the Southern Federal University (Rostov-on-Don) Yuri Tikhonov and Anna Razumnaya, physicists from the French University of Picardy named after Jules Verne Igor Lukyanchuk and Anais Sen, as well as materials scientist from Argonne National Laboratory Valery Vinokur. The article talks about the creation of an “impossible” capacitor with a negative charge, which was predicted decades ago, but has only now been put into practice.
The development promises a revolution in the electronic circuits of semiconductor devices. A pair of a “negative” and a conventional capacitor with a positive charge, connected in series, increases the input voltage level at a given point above the nominal value to that required for the operation of specific sections of electronic circuits. In other words, the processor can be powered by a relatively low voltage, but those sections of the circuits (blocks) that require an increased voltage to operate will receive controlled power with an increased voltage using pairs of “negative” and conventional capacitors. This promises to improve the energy efficiency of computing circuits and much more.
Before this implementation of negative capacitors, a similar effect was achieved for a short time and only under special conditions. Russian scientists, together with colleagues from the USA and France, have come up with a stable and simple structure of negative capacitors, suitable for mass production and for operation under normal conditions.
The structure of a negative capacitor developed by physicists consists of two separated regions, each of which contains ferroelectric nanoparticles with a charge of the same polarity (in Soviet literature they were called ferroelectrics). In their normal state, ferroelectrics have a neutral charge, which is due to randomly oriented domains within the material. Scientists were able to separate nanoparticles with the same charge into two separate physical areas of the capacitor - each in its own area.
At the conventional boundary between two oppositely polar regions, a so-called domain wall immediately appeared - an area of polarity change. It turned out that a domain wall can be moved if voltage is applied to one of the regions of the structure. The displacement of the domain wall in one direction became equivalent to the accumulation of a negative charge. Moreover, the more the capacitor is charged, the lower the voltage on its plates. This is not the case with conventional capacitors. An increase in charge leads to an increase in voltage on the plates. Since the negative and ordinary capacitor are connected in series, the processes do not violate the law of conservation of energy, but lead to the appearance of an interesting phenomenon in the form of an increase in the supply voltage at the desired points in the electronic circuit. It will be interesting to see how these effects will be implemented in electronic circuits.
Source: 3dnews.ru