Charge Orderings and Phase Separations in Itinerant Fermion Systems at Half Filling

• Authors: W. Czart , P. Grzybowski , M. Nogala , S. Robaszkiewicz
• Languages of publication: EN

Abstracts

EN

We analyse the ground state phase diagrams of the charge orderings in narrow band materials using two effective models: (1) the spinless fermion model (t - W) with repulsive intersite interaction (W_{ij} > 0) and (2) the molecular crystal model with the coupling of electrons to intramolecular (crystal field) vibrations. We present results for the case of half filled bands for d = 2 square lattice. The calculations are performed within the (broken symmetry) Hartree-Fock approximation. The study takes into consideration the effects of frustrating next-nearest-neighbour hopping (t_2) on the charge ordered states in these systems. We focus on the two cases: (i) homogeneous phases and phase separations involving checkerboard charge ordering with the nesting vector Q= (π,π) only and (ii) homogeneous phases and phase separations involving two types of charge ordering: (a) checkerboard charge ordering with the nesting vector Q = (π,π), and (b) collinear (CL) charge ordering with Q = (0,π) or Q = (π,0).

Keywords

EN

71.10.Fd; 71.30.+h; 71.45.Lr; 64.75.Gh

Discipline

• 71.30.+h: Metal-insulator transitions and other electronic transitions
• 71.45.Lr: Charge-density-wave systems(see also 75.30.Fv Spin-density waves)
• 71.10.Fd: Lattice fermion models (Hubbard model, etc.)
• 64.75.Gh: Phase separation and segregation in model systems (hard spheres, Lennard-Jones, etc.)

• Journal: Acta Physica Polonica A
• Year: 2012
• Volume: 121
• Issue: 5-6
• Pages: 1042-1044

Dates

published

2012-05

Contributors

author

W. Czart

• Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

author

P. Grzybowski

• Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

author

M. Nogala

• Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

author

S. Robaszkiewicz

• Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

References

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Identifiers

DOI

10.12693/APhysPolA.121.1042