Controlling ferroelectric hysteresis offsets in PbTiO$_{3}$ based superlattices

Abstract

Ferroelectric materials are characterized by degenerate ground states with multiple polarization directions. In a ferroelectric capacitor this should manifest as equally favourable up and down polarization states. However, this ideal behavior is rarely observed in ferroelectric thin films and superlattice devices, which generally exhibit a built-in bias which favors one polarization state over the other. Often this polarization asymmetry can be attributed to the electrodes. In this study we examine bias in PbTiO3-based ferroelectric superlattices that is not due to the electrodes, but rather to the nature of the defects that form at the interfaces during growth. Using a combination of experiments and first-principles simulations, we are able to explain the sign of the observed built-in bias and its evolution with composition. Our insights allow us to design devices with zero built-in bias by controlling the composition and periodicity of the superlattices.

High Velocity, Low‐Voltage Collective In‐Plane Switching in (100) BaTiO3 Thin Films

“…[7] To understand collective switching dynamics a multitude of macroscopic and nanoscale characterization techniques have been employed. On the macroscale, ferroelectric hysteresis, positive-up negativedown (PUND), [8] and capacitance-voltage measurements provide insight into collective switching dynamics. On the nanoscale, a range of scanning-probe-based switching spectroscopes have observed local switching dynamics.…”