Piezoelectricity and related properties in orthorhombic cadmium diiodate

We report a complete investigation of the structural, electronic, vibrational, elastic and piezoelectric properties of the P2(1)2(1)2(1) orthorhombic phase in cadmium diiodate (delta-Cd(IO3)(2)) by combining experiments and first-principles based calculations. We revisited the nature of the electronic band gap and suggest an indirect band gap with a value of 4.6 eV. The infrared and Raman responses were measured and the different phonon modes assigned. To date, the delta-Cd(IO3)(2) piezoelectric response remains unknown. We reported the different mechanisms involved in its piezoelectric response from the density functional perturbation theory. The highest value of the piezoelectric-stress and piezoelectric-strain constants in the zero Kelvin limit is predicted for e(41) = -0.27 C m(-2) and d(41) = -10.32 pC N-1. These sizable values associated with the thermal stability (no phase transition up to the thermal decomposition at 550 degrees C) and a relatively large electronic band gap make delta-Cd(IO3)(2) a potential candidate for piezoelectric applications.