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arXiv · 1610.04035

Coulomb matrix elements in multi-orbital Hubbard models

Jörg Bünemann·Florian Gebhard
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Abstract

Coulomb matrix elements are needed in all studies in solid-state theory that are based on Hubbard-type multi-orbital models. Due to symmetries, the matrix elements are not independent. We determine a set of independent Coulomb parameters for a $d$-shell and a $f$-shell and all point groups with up to $16$ elements ($O_h$, $O$, $T_d$, $T_h$, $D_{6h}$, and $D_{4h}$). Furthermore, we express all other matrix elements as a function of the independent Coulomb parameters. Apart from the solution of the general point-group problem we investigate in detail the spherical approximation and first-order corrections to the spherical approximation.

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Jörg Bünemann, Florian Gebhard. 2017-01-15. Coulomb matrix elements in multi-orbital Hubbard models. https://doi.org/10.1088/1361-648x%2Faa5900

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