Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

"Spintronics" could enable a new generation of electronic devices

11.08.2003


Moore´s Law - a dictum of the electronics industry that says the number of transistors that fit on a computer chip will double every 18 months - may soon face some fundamental roadblocks. Most researchers think there´ll eventually be a limit to how many transistors they can cram on a chip. But even if Moore´s Law could continue to spawn ever-tinier chips, small electronic devices are plagued by a big problem: energy loss, or dissipation, as signals pass from one transistor to the next. Line up all the tiny wires that connect the transistors in a Pentium chip, and the total length would stretch almost a mile. A lot of useful energy is lost as heat as electrons travel that distance.

Theoretical physicists at Stanford and the University of Tokyo think they´ve found a way to solve the dissipation problem by manipulating a neglected property of the electron - its "spin", or orientation, typically described by its quantum state as "up" or "down."

They report their findings in the Aug. 7 issue of Science Express, an online version of Science magazine. Electronics relies on Ohms Law, which says application of a voltage to many materials results in the creation of a current. That´ because electrons transmit their charge through the materials. But Ohm´s Law also describes the inevitable conversion of electric energy into heat when electrons encounter resistance as they pass through materials.



"We have discovered the equivalent of a new `Ohm´s Law´ for spintronics - the emerging science of manipulating the spin of electrons for useful purposes," says Shoucheng Zhang, a physics professor at Stanford. Professor Naoto Nagaosa of the University of Tokyo and his research assistant, Shuichi Murakami, are Zhang´s co-authors. "Unlike the Ohm´s Law for electronics, the new `Ohm´s Law´ that we´ve discovered says that the spin of the electron can be transported without any loss of energy, or dissipation. Furthermore, this effect occurs at room temperature in materials already widely used in the semiconductor industry, such as gallium arsenide. That´s important because it could enable a new generation of computing devices."

Zhang uses a celestial analogy to explain two important properties of electrons - their center of mass and their spin: "The Earth has two kinds of motion. One is that its center of mass moves around the Sun. But the other is that it also spins by itself, or rotates. The way it moves around the Sun gives us the year, but the way it rotates around by itself gives us the day. The electron has similar properties." While electronics uses voltage to move an electron´s center of mass, spintronics uses voltage to manipulate its spin.

The authors predict that application of an electric field will cause electrons´ spins to flow together collectively in a current. The applied electric force, the spins and the spin current align in three different directions that are all perpendicular to each other.

"This is a remarkable thing," explains Zhang. "I push you forward and you move sideways - not in the direction that I´m pushing you."

So far, only superconductors are known to carry current without any dissipation. However, extremely low temperatures, typically -150 degree Celsius, are required for the dissipationless current to flow inside a superconductor. Unlike electronic superconductors being investigated in advanced laboratories throughout the world, whose operating temperatures are too low to be practical in commercial devices, Zhang, Nagaosa and Murakami theorize that the dissipationless spin current will flow even at room temperature.

"This [the work reported in the paper] is a theoretical prediction," Zhang says. "The next step is to work closely with experimental labs to verify this prediction and to demonstrate this effect." That will require creating materials and testing them with a sensitive spin detector. "Once this is done we can go ahead to propose different device structures which take advantage of this effect," he says.

Zhang characterizes his work as fundamental research but says spintronics is already making its way into devices in other labs. With lack of dissipation, spintronics may be the best mechanism for creating ever-smaller devices. The potential market is enormous, he says. "In maybe a 10-year timeframe, spintronics will be on par with electronics," he predicts. "That´s why there´s a huge race going on around the world."

The National Science Foundation and the Department of Energy in the United States and the Ministry of Education, Culture, Sports, Science and Technology in Japan funded the work.

Contact: Dawn Levy, +1-650-725-1944, dawnlevy@stanford.edu

Dawn Levy | EurekAlert!
Further information:
http://news-service.stanford.edu/news/2003/august20/zhang-video-820.html

More articles from Power and Electrical Engineering:

nachricht Fraunhofer ISE Supports Market Development of Solar Thermal Power Plants in the MENA Region
21.02.2018 | Fraunhofer-Institut für Solare Energiesysteme ISE

nachricht New tech for commercial Lithium-ion batteries finds they can be charged 5 times fast
20.02.2018 | University of Warwick

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Researchers invent tiny, light-powered wires to modulate brain's electrical signals

21.02.2018 | Life Sciences

The “Holy Grail” of peptide chemistry: Making peptide active agents available orally

21.02.2018 | Life Sciences

Atomic structure of ultrasound material not what anyone expected

21.02.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>