TY - JOUR
T1 - First principles investigations of MCD spectra and sum rules for 3d transition metal surfaces
AU - Wu, Ruqian
AU - Wang, Dingsheng
AU - Freeman, A. J.
N1 - Funding Information:
We thank Drs Y U Idzerda, GA Prmz and E Badralexe and Mr F Y Rao for helpful dls-cusslons Work supporteda t NorthwesternU m-versltyb y the National ScienceF oundation( Grant No DMR 91-17818a nd by a grant of computer time at the Pittsburgh SupercomputmgC enter throughi ts Dlvlslon of AdvancedS clentlfic Computing) and at Argonne National Laboratory by the Departmento f Energy (grant No W-31-109-ENG-38) One of us (AJF) thanksG ray Prmz for handlmgt he editorial aspectso f this manuscript _ mcludmgt he anonymousr efereemg
PY - 1994/4
Y1 - 1994/4
N2 - Results of precise calculations of the X-ray magnetic-circular-dichroism (MCD) spectra and orbital magnetic moment, 〈Lz〉, based on our thin film full potential linearized augmented plane wave energy band method and a tight binding analysis carried out for Fe(001), Co(0001) and Ni(001) surfaces are shown to provide clear physical insight for this new and exciting phenomenon. In addition to the spin magnetic moment enhancement, the orbital magnetic moment is also found to be enhanced at the surface due to band narrowing. A double peak structure of the MCD spectra for Fe(001) and Co(001) is predicted. For Ni(001), the absorption side peak 6 eV above the main peak is attributed to contributions from the d component in a high-lying state. The MCD orbital sum rule is found to be valid to within 5-10% even in the band approach. However, for the spin sum rule, large errors are found for Ni systems and, in addition, the magnetic dipole term is also found to be very important in this sum rule for atoms without cubic symmetry. This raises a question about the applicability of the spin sum rule to obtain the spin magnetic moment from MCD spectra. Finally, the effects of a photo-induced core hole are found to be strongly screened, and to induce an enhancement of 〈Lz〉.
AB - Results of precise calculations of the X-ray magnetic-circular-dichroism (MCD) spectra and orbital magnetic moment, 〈Lz〉, based on our thin film full potential linearized augmented plane wave energy band method and a tight binding analysis carried out for Fe(001), Co(0001) and Ni(001) surfaces are shown to provide clear physical insight for this new and exciting phenomenon. In addition to the spin magnetic moment enhancement, the orbital magnetic moment is also found to be enhanced at the surface due to band narrowing. A double peak structure of the MCD spectra for Fe(001) and Co(001) is predicted. For Ni(001), the absorption side peak 6 eV above the main peak is attributed to contributions from the d component in a high-lying state. The MCD orbital sum rule is found to be valid to within 5-10% even in the band approach. However, for the spin sum rule, large errors are found for Ni systems and, in addition, the magnetic dipole term is also found to be very important in this sum rule for atoms without cubic symmetry. This raises a question about the applicability of the spin sum rule to obtain the spin magnetic moment from MCD spectra. Finally, the effects of a photo-induced core hole are found to be strongly screened, and to induce an enhancement of 〈Lz〉.
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U2 - 10.1016/0304-8853(94)90305-0
DO - 10.1016/0304-8853(94)90305-0
M3 - Article
AN - SCOPUS:0028408136
VL - 132
SP - 103
EP - 123
JO - Journal of Magnetism and Magnetic Materials
JF - Journal of Magnetism and Magnetic Materials
SN - 0304-8853
IS - 1-3
ER -