Experimentally, hafnia (${\mathrm{HfO}}_2$) has shown a complicated structural configuration space with various metastable phases that are not present in the equilibrium phase diagram. This leads not only to the ferroelectric orthorhombic phase with promising applications, but also to various nonpolar phases that suggest complicated phase transitions and polarization switching paths. To date, the structural configuration space is still not fully explored. In this study, we perform first-principles quantum chemically based searches and identify two alternate nonpolar phases of ${\mathrm{HfO}}_2$, which can be achieved through atomic plane shifts from high-symmetry cubic or tetragonal phases. The metastable phases have lower energy than the tetragonal phase which is commonly believed to be an intermediate state of polarization switching. These phases imply different polarization switching paths with lower barriers and coercive fields for polarization switching in hafnia.

Close

PrevNext

View figure in article

• Ferroelectricity
• Phonons
• Density functional theory