2008/12/05 by Manoranjan Kumar, S. Ramasesha, Z. G. Soos
Materials Science · Physics and Astronomy · #Boundary (topology) #Boundary value problem #Charge (physics) #Charge density wave #Condensed matter physics #Coulomb #Density matrix renormalization group #Electron #Ground state #Hubbard model #Kinetic energy #Organic and Molecular Conductors Research #Periodic boundary conditions #Phase (matter) #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Renormalization group #Superconductivity #cond-mat.other #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.79.035102
9 pages, 7 figures
arxiv created 2008/12/05 · openalex publication_date 2009/01/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Theoretical and computational studies of the quantum phase diagram of the one-dimensional half-filled extended Hubbard model (EHM) indicate a narrow bond-order wave (BOW) phase with finite magnetic gap Em for on-site repulsion U<U^\ensuremath∗, the critical point, and nearest-neighbor interaction Vc\ensuremath≈U/2 near the boundary of the charge-density wave (CDW) phase. Potentials with more extended interactions that retain the EHM symmetry are shown to have a less cooperative CDW transition with higher U^\ensuremath∗ and wider BOW phase. Density-matrix renormalization group is used to obtain Em directly as the singlet-triplet gap, with finite Em marking the BOW boundary Vs(U). The BOW/CDW boundary Vc(U) is obtained from exact finite-size calculations that are consistent with previous EHM determinations. The kinetic energy or bond order provides a convenient new estimate of U^\ensuremath∗ based on a metallic point at Vc(U) for U<U^\ensuremath∗. Tuning the BOW phase of half-filled Hubbard models with different intersite potentials indicates a ground state with large charge fluctuations and magnetic frustration. The possibility of physical realizations of a BOW phase is raised for Coulomb interactions.