Piezoelectric ferromagnetism in two-dimensional materials via materials screening

Abstract

We predict that monolayer ${\mathrm{FeCl}}_{2}$ is a two-dimensional piezoelectric ferromagnet (PFM) with easy-axis magnetism and a Curie temperature of 260 K. Our ab initio calculations combined with data mining reveal 2H-${\mathrm{FeCl}}_{2}$ as the only easy-axis 2D monolayer PFM, and that its magnetic anisotropy increases many-fold with moderate hole doping. We develop an analysis based on magnetic anisotropies densities that explain the magnetic and doping-dependent behavior of ${\mathrm{FeCl}}_{2}$, as well as ${\mathrm{VSe}}_{2}$ and ${\mathrm{CrI}}_{3}$, and can enable the design of future 2D magnetically ordered materials.