New Cloak Promises To Be Invisible To Electrons

Thursday, October 04, 2012

New Cloak Promises To Be Invisible To Electrons

By Belle Dumé
physicsworld.com
10-2-12

Physicists in the US have proposed a way to make an "electron cloak" – an object that is invisible to electrons. Inspired by cloaks that hide objects from light or sound waves, the electron cloak would be made of a tiny structure that is about the same size as the wavelength of electrons it is hiding from. Although the design has not yet been tested in the lab, it could be used to make novel electronic devices and perhaps even help develop better thermoelectric materials for improved energy harvesting and conversion.

Researchers have already succeeded in making "invisibility cloaks" that hide objects from electromagnetic waves. Such cloaks are made from "metamaterials", which are artificial structures with special optical properties such as negative indices of refraction. These structures are arranged in such a way that incoming waves flow smoothly around the cloak, meeting up on the other side as if the cloak was not there. The same principle has also been applied to make cloaks that are invisible to sound waves.

Core and shell

Thanks to quantum mechanics, electrons behave like waves, and now new calculations by Gang Chen and colleagues at the Massachusetts Institute of Technology (MIT) suggest that cloaks for electrons could be made. The researchers have put forward a practical design that would be made of nanoparticles that comprise an inner core and an outer shell. The core–shell nanoparticle could then be embedded in a host semiconductor, so that it does not disturb the flow of electrons. . . .

* Special Thanks To Andrew Ackerley

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