Exchange Enhanced Generalized Susceptibility Function for Paramagnetic Chromium Including Band Structure Effects

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Abstract
We have calculated the exchange enhanced susceptibility function χ(Q) for paramagnetic chromium attempting to include band structure effects in a realistic manner. First, the unenhanced diagonal element χ0(Q, Q) of the susceptibility was calculated from an APW band calculation using the appropriate matrix elements and a Spline‐fit interpolation scheme to produce an effective mesh of 128 000 points in the zone. The result exhibited a peak corresponding to the wave vector of the spin‐density wave in chromium but differed quantitatively from previous calculations which ignored the matrix elements. Next, within the spirit of the RPA, the exchange enhanced susceptibility was obtained by approximately solving the coupled selfconsistent equations between the different Fourier components of the response to an applied field instead of simply dividing by the usual scalar denominator. This resulted in susceptibility functions which look similar to those obtained from a localized Heisenberg‐type Hamiltonian.