Fig. 1
From: Strain engineering of electro-optic constants in ferroelectric materials
a Energy of the tetragonal, monoclinic, and orthorhombic phases with respect to strain. b Sketch of the 5-atom unit cell and the Cartesian axes a1, a2, and a3, as well as the 20-atom supercell and its axes b1, b2, and b3. c c/a ratio in the tetragonal, monoclinic, and orthorhombic supercell. d Calculated piezoelectric constant d33 in the three considered phases. Data indicated in blue circles, green triangles, and red squares correspond to tetragonal, monoclinic, and orthorhombic phases, respectively, in (a, c, d)
