Don Heiman

Both Insulator and Conductor, This Material Will Help Revolutionize Quantum Computing

With the bright red words “CAUTION: HIGH MAGNETIC FIELD” emblazoned at the entrance, the Nanomagnetism Lab at Northeastern looks like something out of a sci-fi film.

A long metal rod with a tangle of thin wires hangs from the door leading to Professor Don Heiman’s office. “This is a cooling unit for a quantum computer,” he explains.

As an experimental physicist, Heiman specializes in spintronic materials. At its core, this field is about taking electricity a step further. Instead of just using it to power devices, the properties of the individual electrons themselves are used to transmit data.

Understanding how to effectively create polarized currents can lead to more efficient devices, leading to lower energy consumption. Mary Knox Merrill / Northeastern University

“Of course, spintronics is about a lot more than just computing,” he notes, gesturing to the many contraptions strewn across the lab.

Electrons have a property called intrinsic angular momentum – quantum spin. This momentum can be either of two opposite values. By polarizing the electrons so that only the ones with specific spin make it through a filter, the electrons can be used to store data or make special materials.

From storing large amounts of data more efficiently and computing faster to creating a fail-safe for quantum computers, the applications for this type of computing is growing. Though one of the biggest problems with quantum computers is their tendency to have more errors than normal computing.

By creating a spintronic device called a topological insulator, which behaves as a conductor on the surface but an insulator in the interior, errors can be reduced. Professor Heiman has an even more pragmatic use.

“Polarized currents dissipate less energy,” he says. Understanding how to effectively create polarized currents can lead to more efficient devices, leading to lower energy consumption.

Doing this, however, has proven tricky. This is why his lab, in conjunction with labs at MIT, Notre Dame, and the NSA, was recently awarded a $90,000 grant from the Division of Materials Science at the NSF. His lab is specifically focused on developing methods to create these special currents at room temperature.

To do this, he is using spin gapless semiconductors and spin filters, which channel electrons into different currents based on their spin. He is working with theoretical labs to create metals called Heusler compounds, which combine these two properties with magnetism to be applied to quantum information processing.

“Quantum computing is the future,” he explains. “If we get this to work, our computers can do calculations a lot faster than the ones we have today.”

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