Piezoelectric ferromagnetism in two-dimensional materials via computational materials screening

A two-dimensional (2D) ferromagnetic system that is also piezoelectric will permit electric field control of magnetism via field-induced strain and structural distortions. Using ab initio computational materials screening, we predict that monolayer FeCl2 is a two-dimensional piezoelectric ferromagnet (PFM) with easy-axis magnetism and a Curie temperature of 260 K [1]. Our density functional theory (DFT) calculations combined with data mining reveal 2H-FeCl2 as the only easy-axis 2D monolayer PFM, and that its magnetic anisotropy increases many-fold with moderate hole doping. We develop post-processing analysis tools using magnetic anisotropy densities that explain the magnetic and doping-dependent behavior of FeCl2, as well as VSe2 and CrI3, and can enable the design of future 2D magnetically ordered materials.

[1] K. Saritas and S. Ismail-Beigi, “Piezoelectric ferromagnetism in two-dimensional materials via materials screening,” Phys. Rev. B, vol. 106, no. 13, p. 134421, Oct. 2022.