'Spin based electronics - smaller, smarter and faster'
Devices get smaller, smarter and faster for each year. The traditional downscaling of devices will, in the future, reach its fundamental limitation. But there is a possible solution - 'spintronics'!
Chalmers Assistant Professor Saroj Dash believes it is, and a new breed of electronics, dubbed “spintronics”, may be the necessary solution. Instead of solely relying on the electron’s charge to manipulate its motion or to store information, spintronic devices would further rely on the electrons spin degree of freedom. The advantage of spin-based electronics is that they are very nonvolatile -retain the stored information even when not powered - compared to charge based electronics. Quantum-mechanical computing based spintronics could therefore achieve speeds unheard of with conventional computing can.
The use of electron spin has already led to many fascinating physical phenomenon and continues to produce more. Spin transport in metal system have demonstrated the potential these phenomena have in electronic technology in the form of, i.e. magnetic read head (in computer Hard Disks) and magnetic random access memory (MRAM). Read heads use GMR (giant magnetoresistance) and TMR (tunnel magnetoresistance) sensors in memory devices of computers and mobile phones. In hard disks, these GMR and TMR read heads have enormously enhanced read and write speed and data storage capacity. Peter Grünberg and Albert Fert were awarded "2007 Nobel Prize in Physics" for the discovery of GMR effect”, Saroj says.
Spin based- Magnetic Random Access Memory (MRAM), a fast emerging next generation memory device.
The recent effort, which is more radical, focuses on finding novel ways of both generation and utilization of spin-polarized currents in semiconducting materials. A recent advancement in the process of semiconductor spintronics was made by Saroj before his time at Chalmers, rather at University of Twente in Enschede, Netherlands. Saroj and his colleagues successfully achieved a spin injection in silicon at room temperature - published in Nature, November 26, 2009. Something that only has been accomplished at minus 150 Celsius degrees before. The interest in integration of silicon into ferromagnetic materials stems from its long spin coherence time and length. This will allow the written information to be processed in integrated circuits and stored for longer time.
In comparison to metal based spintronics devices, by integration of spin functionalities in silicon, the mainstream semiconductor, could impact information technology in ways beyond imagination. By its properties of being able to provide amplification and serve, in general, as multi-functional devices based on the proposed spin transistor concepts. Without risk of overheating, compared to conventional computing, this technology would allow spintronic devices to operate at higher speeds and cut down power consumption in the process.
“This might spark off a revolution in semiconductor industry”, Saroj says.
“In addition, to the near-term studies of various spin transistors and spin transport properties of semiconductors, a long-term and ambitious subfield of spintronics is the application of electron and nuclear spins to quantum information processing and quantum computation”, Saroj adds.
Saroj and his colleagues at Chalmers are currently working on integration of ferromagnetic materials to semiconductor (silicon) and 2-dimentional layered materials such as graphene, in which spins are weakly coupled to other degrees of freedom giving rise to longer spin coherence length.
A proposed Spin Field Effect Transistor (Spin-FET)
Uppdaterad: 08 december 2011
Ansvarig för sidan: Christophe Elehn