Magnetic topological insulators are 1,000 times more energy-efficient for switching

May 15, 2014 by Matthew Chin, University of California, Los Angeles

Magnetic topological insulators developed at UCLA are 1,000 times more energy-efficient for switching
Structure of the two-layer topological insulator developed by UCLA Engineering researchers. Credit: UCLA Engineering
( —Topological insulators are an emerging class of materials that act as both insulators and conductors, and could potentially be used in smartphones, computers and other electronic devices.

A research team at the UCLA Henry Samueli School of Engineering and Applied Science has developed a new class of topological insulators in which one of two layers is magnetized. The advance could lead to the development of much more energy-efficient big-data processing systems and ultra-low power electronics.

Led by Kang Wang, the Raytheon Professor of Electrical Engineering at UCLA and the study's principal investigator, the team demonstrated for the first time that the new topological insulators can be electrically "switched" to make them significantly more energy-efficient than current devices. The research was published April 28 in the journal Nature Materials.

"We are very excited about this important result with the new topological insulators, which should lead to the advancement of future low-power, green electronics," Wang said.

The interiors of topological insulators prevent the flow of electrical currents, but their surfaces allow a current to move with very little resistance. Perhaps most importantly, their surfaces enable the transport of spin-polarized electrons while preventing the "scattering" of electrons that causes energy to be dissipated and wasted.

The created at UCLA comprises two layers, one of which contains chromium, a magnetic element. An electrical current that drives spin-polarized electrons can switch the up-down polarity of the magnetic chromium atoms. This switching is what enables the device to write memory or perform calculations.

Most significantly, the new two-layer structure uses 1,000 times less energy to switch polarity than comparable memory structures.

"This is the first time that topological insulators have been incorporated in a magnetic structure that can be efficiently switched, and is perhaps the first demonstration of potential applicable devices based on topological insulators," said Yabin Fan, the paper's lead author and a UCLA graduate student in .

Explore further: Spintronics: Deciphering a material for future electronics

More information: "Magnetization switching through giant spin–orbit torque in a magnetically doped topological insulator heterostructure." Yabin Fan, et al. Nature Materials (2014) DOI: 10.1038/nmat3973. Received 03 December 2013 Accepted 02 April 2014 Published online 28 April 2014

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not rated yet May 15, 2014
Interesting article, anyone got a feel for how scalable the tech might be? The physics might as well be black magic as far as my understanding goes but it would be good to know of it might be a potential replacement for the IGBT and MOSFET used in high power switching.
5 / 5 (2) May 15, 2014
how scalable the tech might be
There is way more candidates (spinotronic, memristors, FeRAM/FeTRAM, MRAM, phase-change memories, IBM Racetrack, graphene based memories) than the actual projects. Due to financial crisis, the market stalls and the manufacturers prefer to write off their previous huge investments first.
3 / 5 (2) May 15, 2014
Unfortunately there is no accompanying cell structure diagram to show us the architecture of the entirety of the memory cell. It sounds like they are describing STT-MRAM, albeit with so little discussion how this functions to power the MRAM cell itself using 1000 times less energy. The biggest drawback to any MRAM has of course been power consumption, slow "write" is also a problem. I'd sure like to see a circuit diagram so as to see how this two layer topological insulator will interface with a memory cell & using 1000 times less energy to make it function.

Surpassing all the problems with any MRAM is resistive RRAM, its cell structure consumes 20x less power than 15 nanometer NAND & production by Crossbar begins later this year. RRAM is the most promising future of mobile computing when it comes to power consumption efficiency & cost of producing a chipset.

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