Work function change of Ni, HfO2 films and Ni/HfO2 interfaces as a function of external electric field

Abstract

In this paper, the effects of external electric field on the work functions for Ni(001), Ni(111), HfO2(001) and HfO2(111) films and the effective work functions for Ni(001)/HfO2(001) and Ni(111)/HfO2(111) interfaces were studied by first-principles methods based on density functional theory (DFT). It is found that the work functions for all the systems change linearly with the strength of external electric field. Comparing the slopes of the work function variation versus external electric field strength for Ni, HfO2 films and Ni/HfO2 interfaces, we have found that the response of the effective work function to external electric field for Ni/HfO2 interfaces is determined by the response of the HfO2 side to external electric field.