Improvement of ferroelectric phase fraction in HfO2 via La-containing co-doping method

In this work, the effect of co-doping lanthanide and VB group elements on the phase fraction of HfO2 is studied by first-principles calculations. A significant increase in the ferroelectric orthorhombic phase fraction can be achieved by doping La with Ta or Nb, which would enhance the ferroelectricity of HfO2. Furthermore, during the screening process, it is observed that oxygen vacancies coupled with dopants can promote the formation of the ferroelectric phase in HfO2. These studies and results provide valuable methods for improving the ferroelectric properties of HfO2.