Enhanced magneto-optical Kerr effect at Fe/insulator interfaces

Gu, B.; 高橋 三郎*; 前川 禎通

Physical Review B, 96(21), p.214423_1 - 214423_6, 2017/12

AA2017-0686.pdf:0.45MB

https://doi.org/10.1103/PhysRevB.96.214423

Using density functional theory calculations, we have found an enhanced magneto-optical Kerr effect in Fe/insulator interfaces. The results of our study indicate that interfacial Fe atoms in the Fe films have a lowdimensional nature, which causes the following two effects: (1) The diagonal component of the optical conductivity decreases dramatically because the hopping integral for electrons between Fe atoms is suppressed by the low dimensionality. (2) The off-diagonal component of the optical conductivity does not change at low photon energies, but it is enhanced at photon energies around 2 eV, where we obtain enhanced orbital magnetic moments and spin-orbit correlations for the interfacial Fe atoms. A large Kerr angle develops in proportion to the ratio /. Our findings indicate an efficient way to enhance the effect of spin-orbit coupling at metal/insulator interfaces without using heavy elements.