Ni doping induced robust half-metallic property in LaFeO3 from first-principles investigation

As a typical perovskite compound, LaFeO3 has gained a lot of attention due to its peculiar magnetic, electron transport and catalysis properties. It is known that element doping is an effective way to modulate the physical properties of oxides. In the present work, we employed first-principles method within the framework of density functional theory (DFT) to investigate the Ni doping effect on the structure, magnetic and electronic properties of LaFeO3. Three Ni doping concentrations of 0.125, 0.25 and 0.5 were considered to incorporate into the Fe site. Meanwhile, electron correlation effect was taken into account through adding a series of U parameters. The results revealed that Ni doped LaFe1-xNixO3 series is structurally stable from the formation energy and the tolerance factor, and thermodynamically stable from the formation enthalpy. It is suggested that the electron correlation effect plays a vital role in the determination of magnetic ground state and electronic structure. It is found that a transition from G-type antiferromagnetic LaFe0.875Ni0.125O3 and LaFe0.75Ni0.25O3 to ferromagnetic LaFe0.5Ni0.5O3 occurs. Besides, half-metallic property of LaFe1-xNixO3 series is observed due to the extra electron states across the Fermi level introduced by Ni doping in one spin channel. Moreover, the half-metallic property is found to be robust under in-plane tensile and compressive strain for LaFe1-xNixO3 series, indicating its potential application as film devices in spintronics. The results obtained in this work may provide valuable guidance for the understanding of doping physical mechanism, synthesis and performance regulation of LaFeO3-based materials.