Topological waveguide reduces energy consumption in electronics

A team of researchers from the Institute for Materials Research at Tohoku University has developed an acoustic waveguide based on the mathematical concept of topology, which could lead to reduced energy consumption in many everyday electronic devices. Surface acoustic waves (SAW) are a type of acoustic wave where the vibration magnitude is focused on a material’s surface. SAWs can be excited and detected on piezoelectric substrates, crystals with the ability to generate electricity when compressed or vibrated. Electrical components, known as SAW devices, make use of this and provide frequency filtering and sensing in common electronic devices such as mobile phones and touch sensors. However, they consume a lot of energy, thus being a drain on battery life.

The team, which comprised Yoichi Nii and Yoshinori Onose from Tohoku University, created the topological waveguide as a solution to this problem. Waveguides are devices that carry or guide waves in a spatially confined area. Topological waveguides are a recent development that reduce energy loss and allow for manipulating waves in unique ways. The topological nature of the researchers’ waveguide reduces energy consumption and could also prolong the battery life of phones and other electronics.

The waveguide is also easy to create and compatible with current SAW device technology. “Implementing our waveguide involves simply fabricating nano-sized pillar patterns on the surface of the piezoelectric substrate,” Nii said.

The waveguide could drive further breakthroughs in quantum technologies. “SAW-based technologies have also attracted the attention of researchers exploring ways to push the boundaries of quantum computing,” Nii said.

The research findings were published in the journal Physical Review Applied.

Top image caption: A schematic of the topological surface acoustic waveguide. SAW is shown in red and white stripes that propagate into a metallic pillar pattern. The upper (blue) and lower (green) pillar patterns have a distinct topological acoustic property. As a result, a characteristic SAW mode appears along the interface between them. In the experiment, the SAW mode was directly visualised by scanning microwave impedance microscopy (brown). Image credit: Yoichi Nii