Spin wave excitations in the ferromagnetic phase of iron - Study with a tight-binding model

Journal of the Physical Society of Japan

Volumn 76, Issue 4, 2007, Pages

  Naito, Masayuki ^a   Hirashima, Dai S ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

Ferromagnetic Fe; Self energy; Spin wave; Tight binding model

Indexed keywords

EID: 34247096114     PISSN: 00319015     EISSN: 13474073     Source Type: Journal    
DOI: 10.1143/JPSJ.76.044703     Document Type: Article

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32. If we used a conserving scheme to calculate the Green's function, the chemical potential shift and the shape of the fermi surface should be determined self-consistently and this subtraction would be unnecessary. In a non-self-consistent scheme such as the one used in this study, this somewhat ambiguous subtraction is inevitable, but this does not cause an artifact in the following analysis of the quasiparticle dispersion at low energies.
33. We also use a smaller lattice and find that finite size corrections are small. The periodic boundary condition is imposed.
34. We set ℏ = 1.
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38. In calculating the dynamical spin susceptibility using the Green's function obtained with the FLEX, one must consider the vertex corrections that properly correspond to the self-energy correction in order to satisfy the spin rotational symmetry. (Through the vertex corrections, one can take account of mode-coupling effect on the spin wave dispersion.) Otherwise, the correct spin wave dispersion, which vanishes as q → 0, cannot be obtained. However, the actual implementation is much more formidable than the calculation of the Green's function.