TY - JOUR
T1 - Ab initio derivation of low-energy model for κ-ET type organic conductors
AU - Nakamura, Kazuma
AU - Yoshimoto, Yoshihide
AU - Kosugi, Taichi
AU - Arita, Ryotaro
AU - Imada, Masatoshi
PY - 2009/8
Y1 - 2009/8
N2 - We derive effective Hubbard-type Hamiltonians of κ-(BEDT-TTF) 2X, using an ab initio downfolding technique, for the first time for organic conductors. They contain dispersions of the highest occupied Wannier-type molecular orbitals with the nearest neighbor transfer t ∼ 0:067 eV for a metal X - Cu(NCS) 2 and 0.055 eV for a Mott insulator X - Cu 2(CN) 3, as well as screened Coulomb interactions. It shows unexpected differences from the conventional extended Hückel results, especially much stronger onsite interaction U ∼ 0:8eV (U/t ∼ 12{15) than the Hückel estimates (U/t ∼ 7{8) as well as an appreciable longer-ranged interaction. Reexamination on physics of this family of materials is required from this realistic basis.
AB - We derive effective Hubbard-type Hamiltonians of κ-(BEDT-TTF) 2X, using an ab initio downfolding technique, for the first time for organic conductors. They contain dispersions of the highest occupied Wannier-type molecular orbitals with the nearest neighbor transfer t ∼ 0:067 eV for a metal X - Cu(NCS) 2 and 0.055 eV for a Mott insulator X - Cu 2(CN) 3, as well as screened Coulomb interactions. It shows unexpected differences from the conventional extended Hückel results, especially much stronger onsite interaction U ∼ 0:8eV (U/t ∼ 12{15) than the Hückel estimates (U/t ∼ 7{8) as well as an appreciable longer-ranged interaction. Reexamination on physics of this family of materials is required from this realistic basis.
KW - Downfolding
KW - Effective hamiltonian
KW - First-principles calculation
KW - Organic conductors
KW - κ-(BEDT-TTF) Cu (CN)
KW - κ-(BEDT-TTF) Cu(NCS)
UR - http://www.scopus.com/inward/record.url?scp=69149093242&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=69149093242&partnerID=8YFLogxK
U2 - 10.1143/JPSJ.78.083710
DO - 10.1143/JPSJ.78.083710
M3 - Article
AN - SCOPUS:69149093242
SN - 0031-9015
VL - 78
JO - journal of the physical society of japan
JF - journal of the physical society of japan
IS - 8
M1 - 083710
ER -