According to a new paper published today in Nature Materials, the newly engineered material creates a robust acoustic structure that can control in unusual ways the propagation and localization of sound even when fabrication imperfections exist. This unique property may improve technologies that use sound waves, such as sonars and ultrasound devices, making them more resistant to defects. Using topological principles, researchers predicted and later discovered topological insulators—special materials that conduct electric currents only on their edges, not in the bulk. Their unusual conduction properties stem from the topology of their electronic band gap, and they are therefore unusually resistant...