Bartolomeu dos Santos - Academia.edu (original) (raw)
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Karlsruhe Institute of Technology (KIT)
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![Research paper thumbnail of Metal-insulator transitions and dilute electron and hole doping in the extended Hubbard ([ital d]-[ital p]) model](https://attachments.academia-assets.com/70760261/thumbnails/1.jpg)
](Phys Rev B, 1994
Metal-insulator transitions in the three-band extended Hubbard model are studied within the meanf... more Metal-insulator transitions in the three-band extended Hubbard model are studied within the meanfield theory of the Kotliar-Ruckenstein slave-boson formalism. It is shown that the charge-transfer (CT) insulator transition (6 « U) takes place when tune the CT-eneqp loss 2h exceeds eight times the average kinetic-energy gain per site E, contrary to the Mott-Hubbard (MH) transition (U «6) which occurs when the Coulomb-energy loss U exceeds E. The positions of the renormalized d levels of quasiparticles formed on dilute doping are analyzed. A dilute hole doping into the insulator phase gives rise to several qualitatively difFerent doping regimes, e.g. , those with d-hole or d-electron doping determined by some simple rules, in which dilute hole doping just inside the boundary always induces d electron doping. We will show that the dilutely hole-doped phase diagram is remarkably symmetric with respect to U and 5, i.e. , the MH and CT insulators. The optical conductivity gap Eg p of the MH and CT insulators is interpreted as a jump in the chemical potential hp between dilute electron and hole doping, and is strongly renormalized from the bare Hubbard gap U or CT gap 6 near the metal-insulator boundary, while it is roughly given by the bare gap well inside the insulator phase.
Phys Rev B, 1994
Metal-insulator transitions in the three-band extended Hubbard model are studied within the meanf... more Metal-insulator transitions in the three-band extended Hubbard model are studied within the meanfield theory of the Kotliar-Ruckenstein slave-boson formalism. It is shown that the charge-transfer (CT) insulator transition (6 « U) takes place when tune the CT-eneqp loss 2h exceeds eight times the average kinetic-energy gain per site E, contrary to the Mott-Hubbard (MH) transition (U «6) which occurs when the Coulomb-energy loss U exceeds E. The positions of the renormalized d levels of quasiparticles formed on dilute doping are analyzed. A dilute hole doping into the insulator phase gives rise to several qualitatively difFerent doping regimes, e.g. , those with d-hole or d-electron doping determined by some simple rules, in which dilute hole doping just inside the boundary always induces d electron doping. We will show that the dilutely hole-doped phase diagram is remarkably symmetric with respect to U and 5, i.e. , the MH and CT insulators. The optical conductivity gap Eg p of the MH and CT insulators is interpreted as a jump in the chemical potential hp between dilute electron and hole doping, and is strongly renormalized from the bare Hubbard gap U or CT gap 6 near the metal-insulator boundary, while it is roughly given by the bare gap well inside the insulator phase.