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IBM Researchers Confirm Decade-Old Theory of Locking Electron Spin Rotation

Synchronizing spin of electrons extends their spin lifetime to match the cycle of a 1 GHz processor

2 min read
IBM Researchers Confirm Decade-Old Theory of Locking Electron Spin Rotation

 

IBM is again taking the lead in spintronics research. Researchers at IBM Zurich and scientists at ETH Zurich for the first time have shown that electrons can be programmed to spin in unison in a semiconductor in what is called a persistent spin helix.

Importantly, the research, which was published in the journal Nature Physics, demonstrated that synchronizing the electrons in this way extends the spin lifetime by 30 times to 1.1 nanoseconds—the same time it takes for an existing 1GHz processor to cycle. It is expected that this level of control over the spin of electrons could result in more energy efficient electronic devices.

In 2003, a theory was proposed that it was possible to lock the spin rotation of electrons. The IBM and ETH Zurich researchers have not only been able to confirm this theory but also demonstrated that electron spins move tens of micrometers in a semiconductor with their orientations synchronously rotating along a path—not unlike a couple dancing a waltz.

In explaining the electron spin with the waltz metaphor, Dr. Gian Salis of the Physics of Nanoscale Systems research group at IBM Zurich said: “If all couples start with the women facing north, after a while the rotating pairs are oriented in different directions. We can now lock the rotation speed of the dancers to the direction they move. This results in a perfect choreography where all the women in a certain area face the same direction. This control and ability to manipulate and observe the spin is an important step in the development of spin-based transistors that are electrically programmable.”

The researchers were able to achieve this feat by first setting up the ability to monitor the spins of the electrons using a time-resolved scanning microscope technique. The researchers were then able to induce the synchronous spin motion by carefully engineering the spin-orbit interaction—a mechanism that couples the spin with the motion of the electron.

While this research promises to bring a greater level of control to spintronics, this research is far from finding its way into our electronic devices any time soon. For example, the experiments performed by the IBM scientists were performed at 40 Kelvin (-233 C, -387 F)—a temperature not suitable for your tablet computer.

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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.

Avicena

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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