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Enhancing the capacity of memory devices

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A study by Tomsk Polytechnic University has shown that topological vortices found in low-dimensional materials can be displaced and erased and then restored again by the electrical field within nanoparticles.

The study's findings open up opportunities for memory devices or quantum computers in which information will be encrypted in the characteristics of topological vortices.

As modern electronics components become smaller and smaller, so the efficiency of devices can be compromised due to different quantum effects. One way to circumvent these limitations is to use topological vortices as they can be used to generate high density NRAM or quantum computers in which information will be encrypted in the characteristics of topological vortices.

Scientists from TPU and scientific centres in the USA, China and Germany have discovered unusual self-organisation of atoms in the volume of nanoparticles and have used an electric field to control them. These "controlled" nanoparticles can be used to generate capacious non-volatile random access memory (NRAM), quantum computers and other next generation electronics.

The study’s main author, Dmitriy Karpov, an engineer of the Department of General Physics, TPU, says that in modern materials science the defects of matter are divided into two large groups. The first group includes classical, well-studied defects, when atoms in matter are mechanically disordered, the other group doesn’t have any significant changes. Instead, the spatial organisation of the lattice itself changes and such defects are called topological.

Topological defects can strongly influence the matter making it superfluid or superconductive, but these defects are only found only in low-dimensional materials: two-dimensional nanorods and nanofilms (just several atoms thick) and one-dimensional nanodots or nanoparticles which are spherical particles consisting of several tens or hundreds of identical atoms.

"The vortex core is a nanostrand which can be both displaced by the field, and erased and restored again within nanoparticles’, explains Edwin Fohtung, Professor of Los Alamos National Laboratory and New Mexico State University .

The scientists studied barium titanate nanoparticles whose internal structure was visualised with the help of penetrating X-ray radiation from the synchrotron Advanced Photon Source in Chicago. They obtained the image of the volume of nanoparticles with the resolution of 18 nanometers, which enabled them to analyse the slightest changes in the structure. As a result, the researchers showed that external electric field can displace the core of the topological vortex inside the nanoparticle, and when the field is removed, it returns to its original position.

‘All in all, the possibility to control and adjust topological vortices in nanoparticles is important for the creation of new electronics’, concludes Dmitriy Karpov.