Crystallographic structure and ferroelectricity of epitaxial hafnium oxide thin films

Harnessing point-defect induced local symmetry breaking in a tetragonal-HfO2 system through sterically mismatched ion doping

“…Density functional perturbation theory (DFPT) calculations were performed under periodic boundary conditions using the projector-augmented wave (PAW) approach 20,21 implemented in the Vienna Ab initio simulation package (VASP) software 22,23 using the Perdew-Burke-Ernzerhof (PBE) functional 24 to study the point defect-induced local symmetry breaking in Y/La-doped t-HfO 2 at different dimensions. The Perdew-Burke-Ernzerhof (PBE) [16][17][18][24][25][26] functional under the generalized gradient approximation (GGA) is applied to deal with the exchange and correlation interactions.…”

“…16 Ferroelectricity in the HfO 2 system can be observed in its orthorhombic phase. 17 Moreover, to investigate the impact of defect engineering and importing ferroelectricty through point-defect induced local symmetry breaking in the system, a non-ferroelectric phase of the HfO 2 should be selected. Literature is available where emergent ferroelectricity is theoretically found in non-ferroelectric bulk-TiO 2 , 18 and experimentally from SrTiO 3 and low free-standing BaTiO 3 ultrathin films.…”

Optoelectronic Properties of Ferroelectric Composites of Bi3.25La0.75Ti3O12 (BLT) and Co-Doped BLT Thin Films Modified by FeCo-Doped BLT

“…Finally, the BLT/FeCo-BLT and Co-BLT/FeCo-BLT films were deposited on the Nb-doped (0.5 wt.%) Nb-SrTiO 3 (001) substrates used as the bottom electrode. The top electrode was etched by photolithography (Nextron, Busan, Republic of Korea), and a Au top electrode (150 µm diameter) was deposited on the film using a thermal evaporator (Nano Tech Planet Co., Ltd., Bucheon, Republic of Korea) [19,20].…”