Impact of Oxygen Vacancies on Switching Behavior of Ferroelectric $\mathbf{HfO}_{2}$ from First Principle

Ferroelectricity in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{HfO}_{2}$</tex>-based thin films have strong relation with intrinsic oxygen vacancies <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathbf{V}_{\mathbf{O}})$</tex> but the underlying physical mechanisms remain unclear. In this study, we explored the possible role of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{O}}$</tex> on the ferroelectric switching behaviors of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{HfO}_{2}$</tex>-based devices using first principle methods. The results reveal: 1) <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{O}}$</tex> leads to upgraded ferroelectricity by lowering the switching barrier; 2) Disordered <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\mathbf{O}}$</tex> results in symmetric coercive field between polarization states, which mitigates imprint effect. Those features are responsible for the dynamical stability of polarization switching and upgraded endurance behaviors of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{HfO}_{2}$</tex>-based ferroelectric devices.