Figure 2
Structural parameters, energies and Polarizations estimated by first-principles calculations. (A) The bar chart shows the optimized lattice constants of cubic (c and c'), tetragonal (t, t' and t''), orthorhombic (o and o') and monoclinic (m, m' and m'') structures of bulk HfO2 and HCO superlattice. The x-axis represents the lattice constants a, b and c while y-axis denotes their amplitude in angstrom. (B) The monoclinic angle induced in the optimized o'-phase (black bar) and of m'-phase (green bar) of HCO superlattice, and m-phase of bulk HfO2. (C) Total energies of different phases of HfO2 and HCO superlattice relative to their respective optimized cubic structures. (D) Polarization of polar o'-phase (black) and m'-phase (green) of superlattice (black), and o-phase of bulk HfO2. The notations of different structures with prime and without prime represent structures of HCO superlattice and bulk HfO2, respectively.
