A quirky quantum effect is giving researchers a new way to turn stray alternating electrical signals into usable power.
An international team led by Professor Dongchen Qi from the Queensland University of Technology School of Chemistry and Physics and Professor Xiao Renshaw Wang from Nanyang Technological University in Singapore studied the nonlinear Hall effect, or NLHE, in a topological material.
Unlike the classical Hall effect, the NLHE can convert alternating electrical signals directly into direct current. The researchers said that means energy from wireless transmissions or other ambient sources could potentially be turned into usable electricity without conventional diodes or other bulky electronic 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 researchers examined a high-quality topological material known for unusual electronic behaviour and found the nonlinear Hall effect remained stable at room temperature.
They also found temperature changed both the strength and direction of the electrical voltage produced by the material.
At lower temperatures, tiny imperfections in the material had the biggest effect on the quantum response. At higher temperatures, vibrations in the crystal structure became more important.
The team said that shift caused the direction of the generated electrical signal to reverse and revealed a new way to control the effect.
“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.”
The findings were published in Newton in a paper titled “Unraveling scattering contributions to the nonlinear Hall effect in topological insulator Bi2Te3.”
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