Stability, Electronic, Magnetic and Piezoelectric Properties of Two Dimensional Transition Metal Silicates

Two-dimensional van der Waals (2D vdW) materials that display ferromagnetism and piezoelectricity have received increased attention. Despite the recent observation of ferromagnetism in single CrI₃ sheets, developing an air stable and transferable single-layer vdW material that is multiferroic has been challenging. To address this problem, we will report our work on layered transition metal silicates that are derivatives of kaolinites and lizardites with transition metal substituting on Al$^{3+}$ and Mg$^{2+}$ sites using ab-initio calculations. Using Density Functional Theory (DFT), we show that these compounds are stable under varying O$_2$ partial pressure and can be synthesized using a surface assisted method [1]. We show that these materials have finite out-of-plane piezoelectric response thanks to the lack of inversion symmetry and also they can be tailored to be ferrimagnetic with a non-zero net moment.

[1] C. Zhou et al., “Structure of a Two-Dimensional Silicate Layer Formed by Reaction with an Alloy Substrate,” Chem. Mater., vol. 31, no. 3, pp. 851–861, 2019.