Intrinsic anomalous Hall effect in nickel: A GGA + U study
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
84
Journal Issue
14
Date Issued
2011
Author(s)
Fuh, H.-R.
Abstract
The electronic structure and intrinsic anomalous Hall conductivity of nickel have been calculated based on the generalized gradient approximation (GGA) plus on-site Coulomb interaction (GGA + U) scheme. The highly accurate all-electron full-potential linearized augmented plane-wave method is used. It is found that the intrinsic anomalous Hall conductivity (σxyH) obtained from the GGA + U calculations with U=1.9 eV and J=1.2 eV is in nearly perfect agreement with that measured recently at low temperatures while, in contrast, the σxyH from the GGA calculations is about 100% larger than the measured one. This indicates that, as for the other spin-orbit interaction (SOI)-induced phenomena in 3d itinerant magnets, such as the orbital magnetic magnetization and magnetocrystalline anisotropy, the on-site electron-electron correlation, though moderate only, should be taken into account properly in order to get the correct anomalous Hall conductivity. The intrinsic σxyH and the number of valence electrons (Ne) have also been calculated as a function of the Fermi energy (EF). A sign change is predicted at EF=-0.38 eV (Ne=9.57), and this explains qualitatively why the theoretical and experimental σxyH values for Fe and Co are positive. It is also predicted that fcc Ni(1-x)Co(Fe,Cu)x alloys with x being small would also have the negative σxyH with the magnitude being in the range of 500-1400 Ω-1cm-1. The most pronounced effect of including the on-site Coulomb interaction is that all the d-dominant bands are lowered in energy relative to the EF by about 0.3 eV, and consequently, the small minority spin X2 hole pocket disappears. The presence of the small X2 hole pocket in the GGA calculations is attributed to be responsible for the large discrepancy in the σxyH between theory and experiment. © 2011 American Physical Society.
SDGs
Type
journal article