Phys.org August 9, 2023
The mechanical displacements in piezoelectric materials carry along macroscopic electric fields, allowing tunneling of acoustic waves across a vacuum gap beyond the charge-charge interaction distance. However, no rigorous proof of complete acoustic wave tunneling has been presented, and the conditions to achieve complete tunneling have not been identified. Researchers in Finland demonstrated analytically the condition for such phenomenon for arbitrary anisotropic crystal symmetries and orientations, and that complete transmission of the incoming wave occurred at the excitation frequency of leaky surface waves. They also showed that the complete transmission condition could be related to the surface electric impedance and the effective surface permittivity of the piezoelectric material, relevant to realize the complete tunneling experimentally. They supported their findings with numerical results for the maximum power transmittance of a slow transverse wave tunneling between identical ZnO crystals. The results showed that complete tunneling could be achieved for a large range of orientations… read more. Open Access TECHNICAL ARTICLE
Schematic of the system under study.
Credit: Communications Physics volume 6, Article number: 178 (2023)Â