Scientists Invent Tiny Device That Generates Ice-Cold Electricity for Quantum Computers

LAUSANNE, Switzerland — Scientists have created a miniature 2D device that can convert heat into electricity with record-breaking efficiency at temperatures colder than space! This breakthrough could revolutionize how we power sensitive quantum computers and explore exotic physics in extremely cold environments.

In the diary Nanotechnology in naturea team of researchers from Switzerland and Japan have unveiled their electrically tunable “Nernst effect” device made from layers of different materials, atomic in thickness, stacked together. Their tiny chip, measuring just micrometers across, can generate useful electrical signals from small temperature differences as low as a frigid 100 millikelvins—just a fraction of a degree above absolute zero.

The device uses the “Nernst effect,” in which a voltage is generated perpendicular to a temperature gradient and magnetic field in some materials. Although the effect has been known for more than a century, getting it to work well at extremely low temperatures has been a constant challenge—until now.

“We are the first to create a device that matches the conversion efficiency of current technologies but operates at the low magnetic fields and ultralow temperatures required for quantum systems. This work is truly a step forward,” says Gabriele Pasquale, a PhD student at EPFL’s Laboratory of Nanoscale Electronics and Structures (LANES), in a press release.

The key to the team’s success was carefully combining different two-dimensional materials into a “van der Waals heterostructure” – essentially a stack of ultrathin layers held together by weak atomic forces.

They started with a base layer of graphene—a single-atom sheet of carbon with excellent electrical properties. On top, they placed several layers of indium selenide (InSe), a semiconductor with intriguing thermoelectric properties. Then, the entire stack was encased in insulating layers of hexagonal boron nitride for protection.

The researchers created their devices using advanced clean-room techniques to ensure the highest quality and purity of materials. They then cooled the chips to just above absolute zero in a special refrigerator called a dilution refrigerator.

To test the devices, the team used a focused laser to create local heating and sophisticated electronic measurements to detect the resulting signals. They also applied magnetic fields and varied the electrical charge in the device using additional electrodes.

Key Results

The team observed a Nernst effect signal that could be electrically turned on and off at an unprecedented ratio of 1,000 to 1. This means the device can be precisely controlled using standard electronic components.

Even more impressive, they measured a Nernst coefficient—a measure of the effect’s strength—of 66.4 microvolts per kelvin per tesla. That’s the highest value ever recorded at such low temperatures and modest magnetic fields.

The researchers also found that their heterostructure design enhanced the Nernst effect compared to using either graphene or indium selenide alone. This synergistic improvement points to new ways to design improved thermoelectric materials.

“If you think of a laptop in a cold office, the laptop will still heat up as it works, causing the room temperature to rise as well. There is currently no mechanism in quantum computing systems to prevent this heat from disturbing the qubits. Our device could provide this necessary cooling,” Pasquale explains.

Conclusions: Exploring the implications for future technology

This breakthrough discovery has important implications for both fundamental physics and practical applications. In the field of basic science, it provides a new tool for studying exotic quantum states of matter that only appear at ultralow temperatures.

On the application side, the technology could find applications in quantum computers, where precise control of heat flow is key. It could enable new types of quantum sensors or help manage waste heat in superconducting circuits.

The team is currently working to further optimize their devices and explore different material combinations. They are also investigating how to scale up production for practical applications.

“These findings represent a significant advance in nanotechnology and offer the promise of developing advanced cooling technologies necessary for quantum computing at millikelvin temperatures,” Pasquale concludes. “We believe this achievement could revolutionize cooling systems for future technologies.”