A discovery is made that could revolutionize the computer and telecommunications industry

In the month of April 2014, a project in which Pedro L. Galindo, University Professor and member of the Computer Engineering Department of the University of Cadiz (UCA), has participated in has been featured on the cover of the magazine Nature Physics, the well-known international physics magazine. In this project, the discovery made by the co-authors of the project is explained: how to modify in a controlled way the behaviour of a family of revolutionary materials known as topological insulators. These materials are destined to become the forerunners of a new generation of microprocessors with high performance and low energy consumption which will revolutionize the computer, mobile phone, telecommunication and car industries, etc. Remember that nowadays, any industrial, domestic or energy consuming device has a microprocessor incorporated.

In 2007, a new family of materials was discovered in experiments: topological insulators. Since then, a large number of researchers have centred their work on them. These peculiar materials behave in a strange way as they are insulators on the inside but behave like conductive metals on the surface. That is to say, the material behaves like a relatively thick layer of plastic that separates two extremely thin layers of conductive material, with the difference that the whole thing is made of one and the same material: it simply behaves in this way. When this material is only a few atoms thick its surface can conduct electricity with an efficiency of almost 100%.

Under the title “Tuning Dirac states by strain in the topological insulator Bi2Se3”, the project has been carried out over the last few years in collaboration with researchers from the University of Wisconsin (USA) and the University of York (UK). Through this project, it has been demonstrated both theoretically (with DFT simulations) and experimentally (using advanced techniques for determining the distortion from electronic microscope images), that the behaviour of a topological insulating material (Bi2Se3) is proportionally correlated to its distortion. This fact opens the doors to the possibility of using distortion to develop devices whose behaviour can be modified in a controlled way. In this way, for example, the piezoelectric effect could be used and by applying electricity to a crystal, distort it and thereby control the topological insulator dynamically.

Dr. Pedro L. Galindo’s work is the fruit of many years of work at the heart of his research group and focusses on calculating the structural distortion in high resolution images from electronic microscopes. His software for calculating distortion is called Peak Pairs Analysis (PPA), the fundaments of which were published in the magazine Ultramicroscopy, and which has been distributed by the Japanese company HREM Research Inc. (world leaders in software applied to electronic microscopes) since 2009 from their headquarters in Tokyo, via a Temporary Licence Agreement from the UCA. The income from the royalties of this software are the largest source of the UCA’s income from this concept. Over the last few years, the software has been purchased by businesses, research centres and universities of important standing such as SAMSUNG, TOSHIBA, FEI, JEOL, U.S. Air Force, Sandia Labs., Oak Ridge Natl. Lab, Los Alamos Labs., Max-Planck Institute, TU Wien, KBSI Korea, ITRI Taiwan, Osaka Univ., and Beijing Univ. of Technology, among others.

For the development and improvement of this aforementioned software, the UCA’s supercomputer has been used (http://supercomputacion.uca.es), a machine which was financed by European Regional Development Funds (ERDF) in two stages, for a total of nearly a million Euros, and the application, design and implantation of which was led by Pedro L. Galindo and carried out in collaboration with other research groups at the UCA (Dr. Rafael García Roja) and personnel from the central computer service (Abelardo Belaústegui and Gerardo Aburruzaga). This machine, one of the most powerful in Andalusia, is currently in the service of the UCA’s research community.

It is important to emphasize that this project, published in Nature Physics, has as its final objective the manufacturing of real devices of exceptional characteristics. For example, topological insulating materials could be used to wire the components of a microprocessor, allowing the electrons to flow at speeds near to light speed, with a practically non-existent energy consumption, thereby reducing the generation of heat which would allow the calculation speed to be increased enormously.

Full bibliographic information

Y. Liu, Y.Y. Li, S. Rajput, D. Gilks, L. Lari, P. L. Galindo, M.Weinert, V. K. Lazarov and L. Li: “Tuning Dirac states by strain in the topological insulator Bi2Se3” in Nature Physics (Abril, 2014) doi:10.1038 / nphys2898
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