Impact of applied strain on the electron transport through ferroelectric tunnel junctions

Combining nonequilibrium Green's functions with density-functional theory, we have investigated the effect of external strain field on the tunneling electroresistance (TER) of ferroelectric material sandwiched between Pt electrodes. The results show that the strain induced para/ferroelectric phase transitions play an important role in the electronic transport properties of the junction. Sizable enhancements in the resistance are found for the strained ferroelectric junctions with a TER ratio of 9000%. Detail analyses show that the Ti-O displacements along the transport direction in ferroelectric barrier change the effective potential profile, resulting in a giant piezoelectric resistance in the ferroelectric tunnel junctions. (C) 2010 American Institute of Physics. [doi:10.1063/1.3462070]