| Dec 09, 2021 |
Materials from the future
(Nanowerk News) Researchers in the Faculty of Mechanical Engineering at the Technion - Israel Institute of Technology have developed a new physical model for controlling elastic wave propagation – a model that may potentially impact various applications, including acoustic cloaking, enhanced sensing, and energy tunneling.
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The development, which was published in Wave Motion ("The electromomentum effect in piezoelectric Willis scatterers"), was headed by Professor Gal Shmuel and postdoc Dr. René Pernas-Salomón, in collaboration with Rutgers University Professor Andrew Norris and Professor Michael Haberman of Texas A&M University.
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As part of their research, the Technion team developed a new class of metamaterials. These artificially engineered materials exhibit properties not found in natural materials. A prominent example of a metamaterial property is a negative effective mass, which models materials moving in the opposite direction to the force applied to them.
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The team’s metamaterials possess a new metamaterial property, which they term electromomentum. In these metamaterials, momentum is coupled to applied electric fields in a form that does not occur in nature. The property describes the generation of a material’s momentum when it is subjected to an electric field. The momentum balance of a body determines how energy will flow through it in the form of elastic waves. Therefore, the electromomentum offers a new knob to control the energy flow and resultant waves by electrically controlling momentum.
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Among the possible applications of the discovery is acoustic cloaking, in which an object is concealed when the acoustic waves generated around it are identical to the waves that would have been created if the object were not there. The electromomentum property brings us closer to the ability to mimic an environment of this kind by controlling the waves created by the object.
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