Structural, Electrical, and Electromechanical Properties of Inverse Hybrid Perovskites from First-Principles: The Case of (CH3NH3)3OI

Inverse-hybrid perovskites (IHPs) with large polarization have recently been predicted from first-principles computations. We use one representative from the IHP class of materials, (CH3NH3)(3)OI (MA(3)OI), to propose a route to the first-principles prediction of structural and electrical properties, such as polarization, polarization reversibility, and the associated coercive field for hybrid organic-inorganic perovskites. The route relies on the construction of the polarization reversal path that models experimental measurements. Such a path was found to play an important role in the ground-state search as well as in the identification of competing structural variations. The latter is believed to be the origin of the structural disorder that is characteristic of hybrid organic-inorganic perovskites. The application of such an approach to MA(3)OI leads to the prediction of several structural variations that are expected to result in a structurally disordered phase above 766 K and of the polar ground state with a polarization of 25.3 mu C/cm(2) that is reversible with the application of an electric field. The upper estimate for the coercive field associated with homogeneous polarization reversal is 6.9 GV/m. The piezoelectric constants of MA(3)OI are predicted to be an order of magnitude smaller in comparison with a prototypical inorganic ferroelectric PbTiO3; however, the low symmetry of the MA(3)OI structure yields finite values for all components of the piezoelectric tensor. The polarization in MA(3)OI is tunable by the epitaxial strain (11.5% change under 5% epitaxial strain), although less so as compared with PbTiO3.

Automated summary

Inverse-hybrid perovskites with large polarization have been predicted using first-principles computations. A route to predicting structural and electrical properties, such as polarization, polarization reversibility, and coercive field, has been proposed for hybrid organic-inorganic perovskites. Experimental measurements were modeled to identify competing structural variations.