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arXiv · 1208.3954

Ab initio two-dimensional multiband low-energy models of EtMe_3Sb[Pd(dmit)_2]_2 and κ-(BEDT-TTF)_2Cu(NCS)_2 with comparisons to single-band models

Kazuma Nakamura·Yoshihide Yoshimoto·Masatoshi Imada
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Abstract

We present ab initio two-dimensional extended Hubbard-type multiband models for EtMe_3Sb[Pd(dmit)_2]_2 and κ-(BEDT-TTF)_2Cu(NCS)_2, after a downfolding scheme based on the constrained random phase approximation (cRPA) and maximally-localized Wannier orbitals, together with the dimensional downfolding. In the Pd(dmit)_2 salt, the antibonding state of the highest occupied molecular orbital (HOMO) and the bonding/antibonding states of the lowest unoccupied molecular orbital (LUMO) are considered as the orbital degrees of freedom, while, in the κ-BEDT-TTF salt, the HOMO-antibonding/bonding states are considered. Accordingly, a three-band model for the Pd(dmit)_2 salt and a two-band model for the κ-(BEDT-TTF) salt are derived. We derive single band models for the HOMO-antibonding state for both of the compounds as well.

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Kazuma Nakamura, Yoshihide Yoshimoto, Masatoshi Imada. 2012-08-20. Ab initio two-dimensional multiband low-energy models of EtMe_3Sb[Pd(dmit)_2]_2 and κ-(BEDT-TTF)_2Cu(NCS)_2 with comparisons to single-band models. https://doi.org/10.1103/physrevb.86.205117

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