Superconductors are metals which can conduct current even without any resistance, although only far below room temperature. Semiconductors, the foundation of current computer technology, show only low conduction of current, while insulators show no conductivity at all.
Physicists have recently been excited about a new exotic type of materials, so-called topological insulators. A topological insulator is insulating inside the bulk like a normal insulator, while on the surface it shows conductivity like a metal. When a topological insulator is interfaced with a superconductor, a mysterious particle called Majorana fermion emerges, which can be used to fabricate a quantum computer that can run much more quickly than any current computer. Searching for Majorana fermions based on a topological insulator–superconductor interface has thus become a hot race just very recently.
Computer-based materials design has demonstrated its power in scientific research, saving resources and also accelerating the search for new materials for specific purposes. By employing state-of-art materials design methods, Dr. Binghai Yan and his collaborators from the Max Planck Institute for Chemical Physics of Solids and Johannes Gutenberg University Mainz in Germany have recently predicted that the oxide compound BaBiO3 combines two required properties, i.e., topological insulator and superconductivity.
This material has been known for about thirty years as a high-temperature superconductor of Tc of nearly 30 Kelvin with p-type doping. Now it has been discovered to be also a topological insulator with n-type doping. A p-n junction type of simple device assisted by gating or electrolyte gating is proposed to realize Majorana fermions for quantum computation, which does not require a complex interface between two materials.
In addition to their options for use in quantum computers, topological insulators hold great potential applications in the emerging technology of spintronics and thermoelectrics for energy harvesting. One major obstacle for widespread application is the relatively small size of the bulk band gap, which is typically around 0.3 electron-volts (eV) for previously known topological insulator materials. Currently identified material exhibits a much larger energy-gap of 0.7 eV. Inside the energy-gap, metallic topological surface states exist with a Dirac-cone type of band structures.
The research leading to the recent publication in Nature Physics was performed by a team of researchers from Dresden and Mainz around the theoretical physicist Dr. Binghai Yan and the experimental chemists Professor Martin Jansen and Professor Claudia Felser. "Now we are trying to synthesize n-type doped BaBiO3," said Jansen. "And we hope to be soon able to realize our idea."
Petra Giegerich | idw
Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester
CWRU directly measures how perovskite solar films efficiently convert light to power
12.01.2017 | Case Western Reserve University
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Trade Fair News
16.01.2017 | Automotive Engineering
16.01.2017 | Life Sciences