Graphene spintronics: Studies show promise. If you’ve had any contact with the concept of ‘digital devices’ (as in theory of, not the use of) you’ve heard it explained like ‘switches’ (i.e. gates) that are either ON or OFF, zeroes or ones – the binary code – that sort of thing. Information is stored or processed based on a sequence of such ‘switches’ for example as bits and bytes. Most of the computing we’re familiar with, the personal computer in particular, is based on ‘switches’ built with silicon semiconductors. These have served us very well, becoming ever more powerful and less expensive. But there are limits, and the manufacturing process is approaching them; so for the last decade or so the race has been on to develop new ways to perform digital operations. One of those ways is the exploration of what is called spintronics.
The big difference is that in a spintronic device, once the direction of the spin is set, requires no energy (electrical power) to keep it that way. Got that? (Visited 592 times, 1 visits today)
Graphene and 'spintronics' combo looks promising. A team of physicists has taken a big step toward the development of useful graphene spintronic devices. The physicists, from the City University of Hong Kong and the University of Science and Technology of China, present their findings in the American Institute of Physics' Applied Physics Letters. Graphene, a two-dimensional crystalline form of carbon, is being touted as a sort of "Holy Grail" of materials. It boasts properties such as a breaking strength 200 times greater than steel and, of great interest to the semiconductor and data storage industries, electric currents that can blaze through it 100 times faster than in silicon. Spintronic devices are being hotly pursued because they promise to be smaller, more versatile, and much faster than today's electronics.
"Spin" is a quantum mechanical property that arises when a particle's intrinsic rotational momentum creates a tiny magnetic field. And spin has a direction, either "up" or "down. " Manchester, University, Graphene, Spintronics, Carbon, Electron | Researchers unlock spintronics in graphene. The Lieber group is focused broadly on science and technology at the nanoscale - Lieber Research Group. Marcus Group Website. A typical micron-scale quantum device - a quantum dot - is shown above (schematically on the left, an actual electron micrograph on the right.)
Electrons are confined vertically to the ground state of a quantum well located at a GaAs/AlGaAs interface, and form a two- dimensional electron gas (2DEG). A mean free path and coherence length on the order of 10 microns insure that the carriers are coherent and ballistic. Metallic gates deposited by electron beam lithography confine electrons laterally. F. Kuemmeth, H. O. Carbon nanotubes for coherent spintronic devices , Materials Today (in press), arXiv:0912.2745 (2009) . Hans-Andreas Engel, L.
Controlling Spin Qubits in Quantum Dots , (2004). cond-mat/0409294 . R. Spins in few-electron quantum dots , Rev. L.P. Electron Transport in Quantum Dots , NATO ASI Conference Proceedings, ed. by L. L. Quantum Dots , Physics World , June 1998 . Guido Burkard , Theory of solid state quantum information processing , (2004). cond-mat/0409626 . Y. I. G. Modelling of graphene-based spintronic devices. Www.stanford.edu/group/cui_group/papers/107 Guihua graphene supercap.PDF. Pubs.acs.org/doi/pdfplus/10.1021/nl2006142. Centro S3, Istituto Nanoscienze—CNR, via Campi 213/a, 41125 Modena, Italy Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany IPCMS CNRS—Université de Strasbourg, 67034 Strasbourg, France Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France Dipartimento di Fisica, Università di Modena e Reggio Emilia, via Campi 213/a, 41125 Modena, Italy Nano Lett., 2011, 11 (7), pp 2634–2639 DOI: 10.1021/nl2006142 Publication Date (Web): June 7, 2011 Copyright © 2011 American Chemical Society Section: Abstract The possibility to graft nano-objects directly on its surface makes graphene particularly appealing for device and sensing applications.
Citing Articles View all 68 citing articles Citation data is made available by participants in CrossRef's Cited-by Linking service. This article has been cited by 12 ACS Journal articles (5 most recent appear below). Graphene steps toward spintronics - 4/15. University of Manchester scientists have found a way to produce spin current – essentially magnetism – in graphene using current flow, a discovery which could have implications for graphene spintronics.
Manipulating the flow of conventional current in graphene is straightforward. “Pronounced field effect: the dependence of the resistivity on applied gate voltage; was already demonstrated in first graphene reports six to seven years ago and triggered enormous research activity in the field,” Manchester researcher Dr Leonid Ponomarenko told Electronics Weekly. However, the spin of electrons in graphene is not so easily manipulated. In their experiment, the researchers connected spin and charge by applying a relatively weak magnetic field to graphene and found that this causes a flow of spins in the direction perpendicular to electric current, making a graphene sheet magnetised. And the induced magnetism extended over macroscopic distances from the current path without decay. Non-local? Graphene turns spin doctor. Another Spin on Graphene.