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Fresh Spin On Logic

MIT team paves way for a spintronics microprocessor

3 min read

In the last few years, a new type of memory has begun to penetrate the market for nonvolatile data storage. The devices exploit a fundamental yet abstract and elusive property of ­electrons called spin. Because it ­underlies permanent magnetism, spin can be thought of as analogous to ­rotation, with a kind of nanoworld angular momentum. An electron’s spin is proportional to its magnetic momentum, and so when spin-polarized electrical currents flow through different types of magnetized metal, resistance changes can be exploited to store information.

Even more interesting would be a microprocessor using spin. In principle, a device that encoded information using the orientation of electrons could handle data thousands of times as fast as the present-day processors that rely only on charge. ”Instead of an electron being there or not there in the gate of a transistor—basically two pieces of information—think about an electron being able to hold a million pieces of information,” says David Awschalom, a physicist at the University of California at Santa Barbara who specializes in the development of magnetic semiconductors. In addition to being much faster, spintronics processors could be much smaller than present-day processors.

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Two Startups Are Bringing Fiber to the Processor

Avicena’s blue microLEDs are the dark horse in a race with Ayar Labs’ laser-based system

5 min read
Diffuse blue light shines from a patterned surface through a ring. A blue cable leads away from it.

Avicena’s microLED chiplets could one day link all the CPUs in a computer cluster together.


If a CPU in Seoul sends a byte of data to a processor in Prague, the information covers most of the distance as light, zipping along with no resistance. But put both those processors on the same motherboard, and they’ll need to communicate over energy-sapping copper, which slow the communication speeds possible within computers. Two Silicon Valley startups, Avicena and Ayar Labs, are doing something about that longstanding limit. If they succeed in their attempts to finally bring optical fiber all the way to the processor, it might not just accelerate computing—it might also remake it.

Both companies are developing fiber-connected chiplets, small chips meant to share a high-bandwidth connection with CPUs and other data-hungry silicon in a shared package. They are each ramping up production in 2023, though it may be a couple of years before we see a computer on the market with either product.

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