Mechanical and Civil Engineering Seminar

Restructuring materials below the acoustic (AC) phonon mean free path or implementing variations in their elastic properties suggested new perspectives regarding the controllability of the AC and thermal properties of crystals. In this talk, we report on electrically switching and modulating the wavy properties of the coherent AC phonons in various nanoscale quantum structures. The fundamental idea is to design the devices so that a combined use of lateral and vertical electric fields along the symmetry axis can be used to control both the carrier distributions and strain tensor components. This allows us to electrically control features of AC phonons such as the mode, amplitude, phase, and detection sensitivities. The capability to control and manipulate the phononic functionalities with external electric fields is analogous to that for manipulating photons and electrons in major technological devices such as transistor switches and amplifiers and could be useful in realizing integrated phononic circuitry.