Strain and Flexoelectric Engineering for the Electrostatic and Ferroelectric Properties of 2D Materials

Recent discoveries and research on the electrostatic potentials and ferroelectricity in two-dimensional (2D) materials down to the monolayer limit have led to innovative device design for applications in optoelectronics, photonics and flexible electronics. Using an electrostatic physics model, we show that photoinduced strain and structural variations can lead to strong flexoelectricity and modulations of the out-of-plane polarization, providing an alternative and ultrafast switching route for 2D ferroelectrics. Meanwhile, the distorted 2D monolayers induce novel and tunable electrostatic potentials that can be used for engineering properties of adjacent 2D materials. We validate our physics model using first-principles calculations of the electrostatic potentials and polarizations. Our computational approach allows for efficient prediction of large-scale structural effects on the electrostatic and ferroelectric properties of 2D materials towards screening and discovery of novel 2D ferroelectrics.