physicists at UCLA (University of California) set out to design a better transistor and that's discovering a new way of thinking about the structure of space.
Space is generally considered infinitely divisible - given that any two positions, always have an intermediate position between ellas.Pero in a recent study aimed at developing ultra-fast transistors using graphene, researchers Department of Physics and Astronomy at UCLA and the California NanoSystems Institute show that the division of space in places discrete, like a chessboard, can explain how point-like electrons, which have no finite radius, able to take your intrinsic angular momentum or "spin ."
While studying the electronic properties of graphene, Professor Chris Regan and Matthew Mecklenburg graduate student found that a particle can acquire spin to live in an area with two types of positions - "light paintings, dark paintings." The particle appears to spin when the tables are so close together that their separation can not be detected.
"The spin of an electron may arise because the space distances very small is not uniform, but rather segmented, like a chessboard, "said Regan.
Their findings are published in the March 18 issue of Physical Review Letters.
electrons believed to possess spin even though they are point particles without any surface that can possibly rotate, recent work on graphene show that electron spin could emerge due to space at very small distances
which has characteristics of non-uniformity observed a segmented structure similar to a checkerboard with squares triangulares.Crédito. (Image: UCLA CNSI).
the standard model of an electron is shown as a sphere rotating with angular momentum positive or negative as shown in blue and gold in the picture above. But such a scheme is fundamentally flawed because the experimental evidence indicates that electrons are point particles ideals without a finite radius and internal structure that could possibly "rotate". A quantum mechanical model of electron moving in a single graphene layer of graphite (shown as a honeycomb of black lines in the image) shows a possible solution to this enigma.Un graphene electron jumps from carbon atom to carbon atom as if moving on a chessboard with squares triangulares.A low energies triangular boxes are not resolved but the electron acquires a spin "internal" quantum number, which reflects whether the boxes are located on the blue or dorada.Asi electron spin could emerge no rotational motion of substructures but discrete structure like a chess board space. (Image: Chris Regan / CNSI).
In quantum mechanics, "spin up" and "spin down" refer to both types of states can be assigned to an electron. The spin of an electron can only have two values \u200b\u200b- not one, not three or fewer infinity - this helps to explain the stability of matter, the nature of chemical bonding and many other fundamental phenomena.
However, it is unclear how the electron leads the rotation implied by its spin. If the electron had a radio, the area involved should be moving faster than the speed of light, in violation of the theory of relativity . The experiments show that the electron does not have a radio, but is thought to be a pure point particle with any surface or substructure that would rotate.
In 1928, the British physicist Paul Dirac showed that the electron spin is intimately related to the structure of space-time . His elegant argument combined quantum mechanics with special relativity, Einstein's theory of space-time (represented by the famous equation E = mc 2).
Dirac equation, far from merely hosting the spin, I actually exige.Pero while showing that relativistic quantum mechanics requires the spin, the equation does not give a mechanical image to explain how a point particle is the manages to carry angular momentum, spin or why this is two values. Revealing a concept
that is both new and deceptively simple, and Mecklenburg Regan found that the two electron spin values \u200b\u200bcan arise from having two types of pictures - light and dark - in a space like a chessboard. And quantum mechanical model developed while working at the surprisingly practical problem of how to make better transistors on a new material called graphene.
Graphene is a single sheet of graphite is an atomically-thin layer of carbon atoms arranged in a honeycomb structure. First isolated in 2004 by Andre Geim and Kostya Novoselov, graphene has an extraordinary wealth of electronic properties such as high electron mobility and current capacity. In fact, these properties hold promise for revolutionary advances so Geim and Novoselov were awarded the Nobel Prize in 2010 only six years after his achievement.
Regan and Mecklenburg are part of an effort at UCLA to develop very fast transistors using this new material.
"We wanted to calculate the amplification of a transistor from graphene," said Mecklenburg. "Our collaboration was the construction and needed to know whether they would work."
This calculation involved the understanding of how light interacts with electrons in graphene.
The electrons in graphene move hopping carbon atom carbon atom, like jump on a chessboard. The graphene chess boxes are triangular, with dark tables pointing "up" and the light pointing "down." When an electron in graphene absorbs a photon , jump from light to the dark box. Regan Mecklenburg and showed that this transition is equivalent to flipping a spin "up" to "down."
In other words, confining the electrons in graphene to specific discrete positions in space giving the spin. This spin, which is derived from the special geometry of the graphene honeycomb network, is in addition and different from the usual spin carried by the electron. In graphene reflects the additional spin structure unresolved chessboard in the space occupied by the electron.
"My advisor [Reagan] became his PhD studying the electron structure," said Mecklenburg. "So I was very excited to see that the spin can arise from a lattice. It makes you wonder if the usual electron spin could be generated in the same way."
"It is unclear whether this work will be most useful in particle physics or condensed matter," said Regan, "but it would be strange that the honeycomb structure of graphene is the only network capable to generate spin.
read the study HERE
source of information:
http://www.physorg.com/news/2011-03-space -chessboard.html
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