News release

From: Queensland University of Technology (QUT)

A new study has revealed how tiny imperfections and vibrations inside a promising quantum material could be used to control an unusual quantum effect, opening new possibilities for smaller, faster and more efficient energy-harvesting devices.

The international team, led by Professor Dongchen Qi from the QUT School of Chemistry and Physics and Professor Xiao Renshaw Wang from Nanyang Technological University in Singapore, studied the mechanism governing the so-called nonlinear Hall effect (NLHE).

Unlike classical Hall effect, this quantum version allows alternating electrical signals, like those found in wireless or ambient energy sources, to be converted directly into usable direct current without the need for traditional diodes or bulky components.

“The NLHE is a sophisticated quantum phenomenon in condensed matter physics where a voltage is generated perpendicular to an applied alternating current, even in the absence of a magnetic field,” Professor Qi said.

“This effect allows us to convert alternating signals straight into direct current, which is what’s needed to power electronic devices. In principle, it means sensors or chips that could operate without batteries, drawing energy from their environment.”

The team studied a high-quality topological material known for its unusual electronic properties and found that the NLHE remains stable up to room temperature.

The direction and strength of the generated voltage was also found to be controlled by temperature.

At low temperatures, tiny imperfections in the material dominated the behaviour. As the material warmed, natural vibrations of the crystal lattice took over, causing the electrical signal to flip direction.

“Once you understand what’s happening inside the material, you can design devices to take advantage of it,” Professor Qi said.

“That’s when quantum effects stop being abstract and start becoming useful – supporting future applications ranging from self-powered sensors and wearable technology to ultra-fast components for next-generation wireless networks.”

Read the full paper, Unraveling scattering contributions to the nonlinear Hall effect in topological insulator Bi2Te3, published in Newton online.