Physicists at Kiel University discover an unusual state of matter
The existence of an unusual state of matter, a crystal that consists entirely of holes, has been proven at Kiel University. As reported in the latest issue of Physical Review Letters (December 2nd , 2005), an international team led by Professor Michael Bonitz has, for the first time, demonstrated with the help of extensive computer simulations that this exotic phenomenon, the existence of which was hitherto only a subject of speculation, should certainly occur. The physicists have also been able to predict the conditions for its formation.
"We now know that this effect occurs in semiconductors with a certain type of band structure", says Bonitz. "In normal solids, the electrons and holes (which are formed when electrons are excited) are both far extended inside the solid - a consequence of quantum mechanics. Electrons and holes penetrate the material like a liquid". However, when the mass of a hole exceeds a certain critical value - 80 times the mass of an electron - the hole liquid undergoes a spontaneous change to become a crystal. Furthermore, there are strong indications that in semiconductor systems of this kind, a reduction of pressure can result in the formation of Bose condensates of bound electron-hole pairs (so-called excitons). Anticipating the next stage of the research, the physicist explains that "the next exciting problem is to set up an experiment that will confirm our prediction of the crystal of holes". Suitable materials systems for this have already been suggested.
Susanne Schuck | alfa
UNLV study unlocks clues to how planets form
13.12.2018 | University of Nevada, Las Vegas
Unprecedented Views of the Birth of Planets
13.12.2018 | Universität Heidelberg
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.
Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
13.12.2018 | Life Sciences
13.12.2018 | Physics and Astronomy
13.12.2018 | Earth Sciences