The control over field-induced polarization switching in ferroelectric-based devices cannot be achieved without detailed understanding of the role of atomistic effects on polarization reversal including structural defects and interfacial (electro)chemical reactions. This atomistic control over ferroelectric behavior will lead to enhanced functionality of the various ferroelectric-based devices such as memories and field-effect transistors. Since the degree to which various defects can affect ferroelectric properties and their role in mediating polarization switching are still not completely understood, we perform first-principles calculations to unveil the interplay between polarization, conductivity and material properties. For example, we demonstrate that both the titanium TiSr and strontium SrTi antisite defects induce ferroelectric polarization in otherwise nonferroelectric SrTiO₃, while the magnitude of spontaneous polarization in SrTiO₃ can be tuned by controlling the degree of Sr/Ti nonstroichiometry. We are also studying the effect of TiSr antisite in SrTiO₃ on the tunneling electroresistance (TER) in asymmetric Pt/SrTiO₃/Pt ferroelectric tunnel junctions with an attempt to correlate the computational results with experimental observations (as shown in Figure on the right).

Representative publications

Klyukin K. and Alexandrov V. “Effect of Intrinsic Point Defects on Ferroelectric Polarization Behavior of SrTiO₃.”
Physical Review B 95, 035301-035308 (2017)