Fig. 4: Antiferroelastic behavior.
From: Theoretical approach to ferroelectricity in hafnia and related materials
a shows the two symmetry-equivalent m-phase variants that can be obtained as a \({\Gamma }_{4}^{+}\) distortion of the o-ref phase. In (b), we emphasize that the unit cell of the o-I* phase can be obtained by matching the two m-variants in (a). Hence, o-I* can be seen as composed of ultra-thin ferroelastic stripe domains (marked with dotted lines), with a domain wall energy of 126 mJ m−2.
