First-principles study on the electromagnetic properties of Co-doped ZnO surface structures controlled by electric field

Abstract

This work studies the electric-field control and control mechanism of the electrical and magnetic properties of the (1̅00) surface of Co-doped and oxygen-vacancy (VO)-doped ZnO (ZnO:Co(1̅00)-Vo) based on first-principles calculations. When there is no external electric field, the total magnetic moment is 5.74μB, and the magnetism originates from the double-exchange interaction between Co atoms. When the external electric field is equal to −0.9 eV/Å, the total magnetic moment of the system decreases to 3.28μB. When the external electric field is equal to −0.7 or 0.9 eV/Å, the total magnetic moment of the system tends to zero, and antiferromagnetism emerges. The magnetism is caused by bound polarons. At the same time, as the external electric field increases, the Fermi level increases. When the external electric field is 0.5 eV/Å, the effective mass of ZnO:Co(1̅00)-VO in the Γ–X direction decreases, and the mobility increases from 5.68 to 11.63 cm2/(V s). These findings will have a reference value for the design of magnetic memories.