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Breakthrough controls the spin of electrons via all electric means

Many of the electronic devices in your home transmit data by controlling the movement of the charge in an electron. Researchers and scientists have found that by using a different means that controls the spin of an electron rather than its charge, transistors would require less energy and create less heat while being able to operate at faster speeds.

The field of research into controlling the spin of an electron is called spin electronics or spintronics for short. A group of researchers at the University of Cincinnati has developed a novel way to control the spin of electrons using pure electric means. The researchers have published their findings in Nature Nanotechnology.

Before the researchers made their breakthrough, the only way to control the spin of electrons was by using local ferromagnets in device architectures. The scientists say that this technique results in design complexities when the demands for electronics require smaller and smaller transistors.

Philippe Debray, research professor in the Department of Physics in the McMicken College of Arts & Sciences said, "Until now, scientists have attempted to develop spin transistors by incorporating local ferromagnets into device architectures. This results in significant design complexities, especially in view of the rising demand for smaller and smaller transistors. A far better and practical way to manipulate the orientation of an electron's spin would be by using purely electrical means, like the switching on and off of an electrical voltage. This will be spintronics without ferromagnetism or all-electric spintronics, the holy grail of semiconductor spintronics."

The team used a device called a quantum point contact for their breakthrough. Debray said, "We used a quantum point contact — a short quantum wire — made from the semiconductor indium arsenide to generate strongly spin-polarized current by tuning the potential confinement of the wire by bias voltages of the gates that create it."

He continued saying, "The key condition for the success of the experiment is that the potential confinement of the wire must be asymmetric — the transverse opposite edges of the quantum point contact must be asymmetrical. This was achieved by tuning the gate voltages. This asymmetry allows the electrons — thanks to relativistic effects — to interact with their surroundings via spin-orbit coupling and be polarized. The coupling triggers the spin polarization and the Coulomb electron–electron interaction enhances it."

The team says that the next step in their research is to achieve the same results at higher temperatures using a different material like gallium arsenide.



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By nineball9 on 10/28/2009 2:36:59 PM , Rating: 3
Wrong.

1) "Your home electronics" already contains items using these substances. You will want to throw out your cell phones, anything using a laser diode (CD, DVD etc), remote control units, and solar cells. Many of these devices use GaAs semiconductors.

2)From Wkikpedia: "On one hand, due to its arsenic content, it is considered highly toxic and carcinogenic. On the other hand, the crystal [gallium arsenide] is stable enough that ingested pieces may be passed with negligible absorption by the body."

http://en.wikipedia.org/wiki/Gallium(III)_arsenide

3)There are many metals like lead, cadmium, mercury which are much more toxic than arsenic (a metalloid) compounds. These are not uncommon in the average home.

Toxic metal list: http://en.wikipedia.org/wiki/Toxic_metal


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