October 13, 2012
Cloaking Techniques Could Help Future Electronic Devices
Lee Rannals for redOrbit.com - Your Universe Online
The power of cloaking mechanisms could eventually lead the way for developing more efficient thermoelectric devices and new kinds of electronics.
MIT researchers applied the idea of harnessing the cloaking mechanisms developed to shield objects from view, to the movement of electrons.
Previous work relied on metamaterials made of artificial materials with unusual properties. The composite structures used for cloaking cause light beams to bend around an object, and then meet on the other side.
“We were inspired by this idea,” said Gang Chen, the Carl Richard Soderberg Professor of Power Engineering at MIT, who decided to study how it might apply to electrons instead of light.
The team, writing in the journal Physical Review Letters, said they modeled nanoparticles with a core of one material and a shell of another.
Rather than bending around the object, the electrons actually pass through the particles.
Computer simulations show that the concept appears to work, and now the team will just try to actually build devices to see whether they perform as expected.
“This was a first step, a theoretical proposal,” said MIT graduate student Bolin Liao. “We want to carry on further research on how to make some real devices out of this strategy.”
The initial concept was developed using particles embedded in a normal semiconductor substrate. Now, the team would like to see if results can be replicated with other materials.
The team's initial impetus was to optimize the materials used in thermoelectric devices. These devices require a combination of characteristics that are hard to obtain, but simulations show this electron-cloaking material could help meet these requirements.
Simulations used particles a few nanometers in size, matching the wavelength of flowing electrons and improving the flow of electrons at particular energy levels by orders of magnitude compared to traditional doping strategies. The team said that this might lead to more efficient filters or sensors.
Chen says as the components on computer chips get smaller, "we have to come up with strategies to control electron transport."
The concept could lead to a new kind of switch for electronic devices, according to Chen. This switch could operate by toggling between transparent and opaque to electrons, turning a flow of them off and on.
“We´re really just at the beginning,” Chen said. “We´re not sure how far this is going to go yet, but there is some potential” for significant applications.