Emergent energy conversion effects arising from symmetry engineering

Energy transduction has been an intensively and extensively studied topic for decades, due to its fundamental interests and technological importance. Just like any other physical effects, symmetry plays an essential role in energy transduction. For instance, only noncentrosymmetric materials possess the piezoelectric effect that converts mechanical energy to electricity and vice versa; materials with polar symmetry show the pyroelectric effect that generates electricity once sensing a temperature variation. Here, we would like to introduce two emergent energy conversion effects induced by symmetry engineering, i.e. the interface piezoelectric effect and interface pyroelectric effect. The built-in electric field developed at the heterostructure interfaces, such as Schottky junctions, induces interface polar symmetry, giving rise to piezoelectric and pyroelectric effects, even though the component materials are centrosymmetric^[1]. These new effects function in materials of any symmetry and, more importantly, they exhibit coefficients comparable and even larger than conventional bulk materials, demonstrating their potentials in technological applications.

References:
[1] M.-M. Yang et al. Nature 584, 377(2020)