Piezoelectricity in K1− xNa xNbO3: First-principles calculation*
Li Qiang, Zhang Rui†, Lv Tian-Quan‡, Zheng Li-Mei
       
Calculated energy as a function of Na content ( x ) for the rhombohedral, orthorhombic, and tetragonal K1− x Na x NbO3. Here we subtract the energy E REF of the rhombohedral K1− x Na x NbO3 from the energy E 0 of each phase.