Oxygen vacancy dynamics in redox-based interfaces: tailoring the memristive response

FERREYRA, CRISTIAN; ROMÁN ACEVEDO, WILSON; GAY, RALPH; RUBI, DIEGO; SÁNCHEZ, MARÍA JOSÉ

JOURNAL OF PHYSICS - D (APPLIED PHYSICS)

IOP PUBLISHING LTD

Año: 2019 vol. 53

0022-3727

Redox-based memristive devices are among the alternatives for the next generation ofnon-volatile memories, but are also candidates for emulating the behavior of synapses inneuromorphic computing devices. Nowadays it is well established that the motion of oxygenvacancies at the nanoscale is the key mechanism for reversible switching of metal/insulator/metalstructures from insulating to conducting, i.e. to accomplish the resistive switching effect. Thecontrol of oxygen vacancy dynamics has a direct effect on the resistance changes, and thereforeon different properties of memristive devices such as switching speed, retention, endurance andenergy consumption. Advances in this direction demand not only experimental techniques thatallow the measurement of oxygen vacancy profiles but also theoretical studies that shed light onthe mechanisms involved. With these goals in mind we analyze the oxygen vacancy dynamics inredox interfaces formed when an oxidizable metallic electrode is in contact with the insulatingoxide. We show how the transfer of oxygen vacancies can be manipulated by the use of differentelectrical stimulus protocols that allow optimization of device figures such as the ON/OFF ratioor writing energy dissipation. Analytical expressions for both high- and low-resistance statesare derived in terms of total oxygen vacancies transferred at the interface. Our predictions arevalidated with experiments performed in Ti/La 1/3 Ca 2/3 MnO 3 redox memristive devices.