article_snippet: This makes many of This atoms release some, or all, of some electrons.
article_snippet: However, with a frequency of nearly a trillion hertz, the sound wave produced is six million times higher in frequency than anything that can be heard by a mammal.
article_snippet: It is also almost the highest frequency possible in such a material.
article_snippet: The research, published in Physical Review Letters, was funded by the Engineering and Physical Sciences Research Council and the Tata Institute of Fundamental Research.