Wonder conductors to keep your laptops and mobiles coolerBy ANI
Thursday, September 2, 2010
LONDON - It’s a common phenomenon for laptops and mobiles to become blisteringly hot after an hour or two of use, but a new wonder conductor could change all that.
In the past five years, physicists Charles Kane and Eugene Mele of the University of Pennsylvania in Philadelphia have uncovered a new kind of material that can keep electrons on the straight and narrow, eliminating collisions and slashing the amount of heat produced.
They are called topological insulators and conduct electricity by harnessing a quantum-mechanical property of electrons called spin. Insulators are the very opposite of conductors: their electrons are tightly bound to atoms and the material resists the flow of electrical current, reports The New Scientist.
The electron revolves around the nucleus in an orbit, tied to it by a magnetic field from the passing nucleus. However, it has its own mini-field as a result of its quantum-mechanical spin. Spin is akin to the rotation of a spherical particle around its axis one-way or the other, and it creates a magnetic field either from its north to its south pole.
In materials where the spin-orbit interaction is strong, a spin-up electron will be deflected in one direction on encountering a nuclear magnetic field, while a spin-down nucleus will be deflected in the opposite direction - an effect dubbed the quantum spin Hall effect.
In a slice of the right material one atom thick, Kane and Mele showed, this would result in no conduction, as electrons deflected in opposite ways around adjacent nuclei would cancel each other out.
At the edge of the material, however, with no adjacent nucleus available on one side, the net result would be a flow of spin-up electrons in one direction around the edge, and a flow of spin-down electrons in the opposite direction.
The find is published in Physical Review Letters. (ANI)