The effect of combined electrical and thermal cyclic loading on the mechanical behaviour of HfO₂nanofilm. A molecular dynamics study

We present an atomistic computational study of electric field and thermal effects on the mechanical behaviour of memristor material HfO2. Memristor materials are used for neuromorphic computation which promises to decrease energy consumption and improve the efficiency of important computational tasks, such as perception and decision making. In our study, first, the atomistic model of HfO2 is built on a monoclinic lattice structure. Then, tensile tests have been carried out to study its mechanical behaviour. Since the material has non-symmetric crystal structure, we observe varied tensile properties along the x, y and z directions. In addition, the effects of electrical field on mechanical behaviour are studied by varying the electrical field intensity from 0 to 0.3 v/Å gradually. For each case, atomistic snapshots are taken to identify the changes occur in the structure due to the electric field. A significant structural damage on the crystal structure of HfO2 is observed after applying 0.3 v/Å electric field, whereas the structural change is insignificant when the magnitude of the electric field is 0.2 v/Å or less. To understand more about the damage of this material, shear loads are applied in different directions and their responses are studied elaborately in this paper.