Structure and stability of La- and hole-doped hafnia with/without epitaxial strain.

The significance of hafnia in the semiconductor industry has been amplified following the unearthing of its ferroelectric properties. We investigated the structure and electrical properties of La- and hole-doped HfO 2 with/without epitaxial strain by first-principles calculations. It is found that the charge compensated defect with oxygen vacancy (LaHfVO) and uncompensated defect (LaHf), compared to the undoped case, make the ferroelectric orthorhombicPca21phase ( o phase) more stable. Conversely, the electrons compensated defect (LaHf+ e ) makes the nonpolar monoclinicP21/cphase ( m phase) more stable. Furthermore, both pure hole doping (without ions substituent) and compressive strain can stabilize the o phase. Our work offers a new perspective on enhancing the ferroelectricity of hafnia.