Thomas-Fermi interfacial screening with voltage-dependence of the screening lengths and influence of oxygen vacancies in MFTJs

Magnetic tunnel junctions with ferroelectric (FE) barrier (MFTJs) are simulated within modified transport model and compared with experimental samples. As a novelty, linearized approach of Thomas Fermi screening is utilized for a simulation of the tunneling behavior through the magnetic metal/dielectric, magnetic metal/ferroelectric (MM/DE, MM/FE) and non-magnetic metal/ferroelectric (NM/FE) interfaces, where the screening length for each interface changes with applied voltage, accounting the growing penetration of the electric field into the metal. In this work, current density (J) and tunnel electroresistance (TER) vs the applied voltage (V) are compared for NM/FE(3nm)/MM and NM/DE/ FE(5nm)/DE/MM junctions. In addition, the impact of oxygen vacancies located on the interfaces is incorporated in the model for NM/DE/FE(5nm)/DE/MM system. As a result, theoretical model modification allows to reproduce experimental data with a better precision than previous approach with a constant screening lengths.