Schottky Barrier Control of Self-Polarization for a Colossal Ferroelectric Resistive Switching

Controllingthe domain evolution is critical both for optimizingferroelectric properties and for designing functional electronic devices.Here we report an approach of using the Schottky barrier formed atthe metal/ferroelectric interface to tailor the self-polarizationstates of a model ferroelectric thin film heterostructure system SrRuO3/(Bi,Sm)FeO3. Upon complementary investigationsof the piezoresponse force microscopy, electric transport measurements,X-ray photoelectron/absorption spectra, and theoretical studies, wedemonstrate that Sm doping changes the concentration and spatial distributionof oxygen vacancies with the tunable host Fermi level which modulatesthe SrRuO3/(Bi,Sm)FeO3 Schottky barrier andthe depolarization field, leading to the evolution of the system froma single domain of downward polarization to polydomain states. Accompaniedby such modulation on self-polarization, we further tailor the symmetryof the resistive switching behaviors and achieve a colossal on/offratio of similar to 1.1 x 10(6) in the corresponding SrRuO3/BiFeO3/Pt ferroelectric diodes (FDs). In addition,the present FD also exhibits a fast operation speed of similar to 30ns with a potential for sub-nanosecond and an ultralow writing currentdensity of similar to 132 A/cm(2). Our studies provide a wayfor engineering self-polarization and reveal its strong link to thedevice performance, facilitating FDs as a competitive memristor candidateused for neuromorphic computing.

Automated summary

In this study, the authors utilize the Schottky barrier at the metal/ferroelectric interface to control the self-polarization states of a ferroelectric thin film heterostructure. Through investigation and theoretical studies, they demonstrate that doping with Sm changes the concentration and distribution of oxygen vacancies, which alters the Schottky barrier and depolarization field, resulting in the evolution of the system from single domain to polydomain states. By engineering self-polarization, they also achieve significant improvement in the resistive switching behaviors of the ferroelectric diodes (FDs). This research provides insights into self-polarization and its impact on device performance, making FDs a competitive memristor candidate for neuromorphic computing.