Figure 4. Theoretical study.

(a) A schematic diagram of the computational model with the induced charge density. The induced charge density at an electric field of +0.732 V nm⁻¹ in the MgO is subtracted from the induced charge density at −0.732 V nm⁻¹. Electric fields of ∓0.732 V nm⁻¹ induce δn_total=±0.03, where δn_total is the total induced holes of the Pt-1 atom. The blue and red areas represent the hole accumulation and depletion, respectively. (b) The perpendicular MAE (ΔE) of each monatomic layer calculated with equation (6), where ↑ and ↓ denote the majority and minority spin bands, respectively. (c) The voltage-induced perpendicular MAE changes (δE) calculated with equation (6). The MAE at +0.732 V nm⁻¹ is subtracted from the MAE at −0.732 V nm⁻¹. The spin-flip-term-induced values of MAE (E_↓↑ and E_↓↑) of the Pt-1 layer provide the dominant contribution to the perpendicular MAE and its voltage-induced change.