多铁和磁电材料的第一性原理研究（英文）

多铁和磁电材料的第一性原理研究（英文）First-principles Study of Multiferroic and Magnetoelectric MaterialsMultiferroic

多铁和磁电材料的第一性原理研究（英文） First-principles Study of Multiferroic and Magnetoelectric Materials Multiferroic and magnetoelectric materials have garnered alot of attention in recent years due to their potential for technological applications such as data storage and information processing. These materials exhibit unique properties such as the coexistence of magnetic and ferroelectric order, allowing for control of magnetization via electric fields and vice versa. First-principles calculations based on density functional theory (DFT) have been used extensively to investigate the electronic and magnetic properties of these materials. In multiferroic materials, the coupling between magnetic and ferroelectric orders occurs through the spin-orbit coupling (SOC) mechanism. This coupling arises from the relativistic correction to the Schrödinger equation and leads to the generation of an electric field by the magnetic order in the presence of external magnetic fields. By performing DFT calculations, it is possible to accurately predict the strength and direction of this coupling in multiferroic materials. For example, in the prototypical multiferroic material bismuth ferrite (BiFeO3), the electronic structure has been studied using DFT calculations. It has been found that the ferroelectric polarization arises from the off-center displacement of the Bi and Fe ions, while the magnetic order is due to the antiferromagnetic arrangement of the Fe spins. The SOC-induced coupling between the magnetic and ferroelectric orders leads to the modulation of the magnetic order by the ferroelectric polarization. Magnetoelectric materials, on the other hand, exhibit adirect coupling between magnetic and electric properties that is not necessarily due to SOC. DFT calculations have been used to design and predict the properties of such materials. For example, the magnetoelectric effect in the hexaferrites BaFe12O19 and SrFe12O19 has been studied using first-principles calculations. It has been predicted that the magnetoelectric effect in these materials can be enhanced by doping with transition metals, and this has been experimentally observed as well. Another class of magnetoelectric materials are the magnetic oxide thin films grown on piezoelectric substrates. In these materials, the magnetization can be controlled by the strain induced in the substrate through the piezoelectric effect. DFT calculations have been used to