However, physicists of the University of Würzburg are paving the way for them: In the American scientific journal "Science", the researchers now present a semiconductor that transmits electric current without heating up in the process.
This new type of semiconductor consists of mercury telluride and mercury cadmium telluride. In a sophisticated procedure, the Würzburg physicists apply these two materials to penny-sized crystal wafers in alternate ultra-thin layers. "The individual layers are only seven to ten nanometers thin," says Professor Laurens Molenkamp. In other words, inconceivably fine: A nanometer is one millionth of a millimeter.
Tiny wire fabricated
In order to analyze the conductivity of the layered material, the physicists structured its surface, using lithographic patterning methods. They sort of created tiny wires in a specific pattern, e.g. an H-shaped structure.
"The material was expected to become an insulator under certain conditions - at very low temperatures, for instance. All conventional semiconductors exhibit this behavior," explains Professor Hartmut Buhmann, who works in Molenkamp's team.
Material reacted in an unexpected way
The physicists were in for a surprise, when the material behaved differently: The electrons concentrated at the edges of the H-shaped structure. In addition to this, they were freely moveable there - without any resistance and thus without dissipating heat. According to the physicists, this characteristic is based wholly on the materials and the way they are layered. The form of the structure - whether H or X - is irrelevant.
Not yet ready for application
This new type of semiconductor is not yet ready for real-world applications, though. The effect described above occurs only at extremely low temperatures below minus 170 degrees Celsius. Therefore, the Würzburg researchers now intend to develop other materials, which produce the same effect at significantly higher temperatures.
"We are going to use bismuth compounds for this purpose," says Laurens Molenkamp. However, they first have to work out a procedure allowing them to stack these materials as well in neat wafer-thin layers.
To stay cool is important for computers
When computers are processing, they heat up. But if temperatures get too high, the function of computer chips is adversely affected, which means they need cooling. The cooling is provided by fans on board the PC or by air conditioning systems in large computer rooms. Some high-performance computers of today are already equipped with water-cooling systems.
So heat is a factor that considerably limits the development of faster computers. This is because more and more transistors, working ever faster, have to be tightly packed on the chips in order to reach higher levels of performance. "Consequently, a higher amount of electric current passes through the chips, inducing an increased heat build-up in the components," explains Hartmut Buhmann. Hence, the advent of components that conduct electric current without generating heat would be likely to give a big push to the evolution of computers.
Nonlocal Transport in the Quantum Spin Hall State, Andreas Roth, Christoph Brüne, Hartmut Buhmann, Laurens W. Molenkamp, Joseph Maciejko, Xiao-Liang Qi, Shou-Cheng Zhang, Science, 17. Juli 2009, Vol. 325, no. 5938, pp. 294-297, DOI: 10.1126/science.1174736
Prof. Dr. Laurens Molenkamp, Chair of Experimental Physics III, University of Würzburg, phone ++49 (931) 888-4925, email@example.com
Prof. Dr. Hartmut Buhmann, phone ++49 (931) 888-5778, firstname.lastname@example.org
Robert Emmerich | idw
Five developments for improved data exploitation
19.04.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
Smart Manual Workstations Deliver More Flexible Production
04.04.2017 | Deutsches Forschungszentrum für Künstliche Intelligenz GmbH, DFKI
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Earth Sciences
25.04.2017 | Life Sciences
25.04.2017 | Earth Sciences