We have performed extensive density matrix renormalization group (DMRG) studies of the Hubbard model on a honeycomb ladder. The band structure (with Hubbard $U=0$ ) exhibits an unusual quadratic band touching at half-filling, which is associated with a quantum Lifshitz transition from a band insulator to a metal. For one electron per site, nonzero $U$ drives the system into an insulating state in which there is no pair-binding between added electrons; this implies that superconductivity driven directly by the repulsive electron-electron interactions is unlikely in the regime of small doping, $x\ensuremath{\ll}1$. However, the divergent density of states as $x\ensuremath{\rightarrow}0$, the large values of the phonon frequencies, and an unusual correlation induced enhancement of the electron-phonon coupling imply that lightly doped polyacenes, which approximately realize this structure, are good candidates for high-temperature electron-phonon driven superconductivity.We have performed extensive density matrix renormalization group (DMRG) studies of the Hubbard model on a honeycomb ladder. The band structure (with Hubbard $U=0$) exhibits an unusual quadratic band touching at half-filling, which is associated with a quantum Lifshitz transition from a band insulator to a metal. For one electron per site, nonzero $U$ drives the system into an insulating state in which there is no pair-binding between added electrons; this implies that superconductivity driven directly by the repulsive electron-electron interactions is unlikely in the regime of small doping, $x\ensuremath{\ll}1$. However, the divergent density of states as $x\ensuremath{\rightarrow}0$, the large values of the phonon frequencies, and an unusual correlation induced enhancement of the electron-phonon coupling imply that lightly doped polyacenes, which approximately realize this structure, are good candidates for high-temperature electron-phonon driven superconductivity.

arXiv:1307.7676Physical Review BDec 27, 201318 citations

Mott-hubbard metal-insulator transition

Arianna Montorsi, Mario Rasetti

Il Nuovo Cimento DOct 1, 19943 citations

Metal-insulator transition in the one-dimensional Holstein model at half filling

Eric Jeckelmann, Chunli Zhang, Steven R. White

We study the one-dimensional Holstein model with spin- $\frac{1}{2}$ electrons at half filling. Ground-state properties are calculated for long chains with great accuracy using the density-matrix renormalization-group method and extrapolated to the thermodynamic limit. We show that for small electron-phonon coupling or large phonon frequency, the insulating Peierls ground state predicted by mean-field theory is destroyed by quantum lattice fluctuations and that the system remains in a metallic phase with a nondegenerate ground state and power-law electronic and phononic correlations. When the electron-phonon coupling becomes large or the phonon frequency small, the system undergoes a transition to an insulating Peierls phase with a twofold degenerate ground state, long-range charge-density-wave order, a dimerized lattice structure, and a gap in the electronic excitation spectrum.We study the one-dimensional Holstein model with spin-$\frac{1}{2}$ electrons at half filling. Ground-state properties are calculated for long chains with great accuracy using the density-matrix renormalization-group method and extrapolated to the thermodynamic limit. We show that for small electron-phonon coupling or large phonon frequency, the insulating Peierls ground state predicted by mean-field theory is destroyed by quantum lattice fluctuations and that the system remains in a metallic phase with a nondegenerate ground state and power-law electronic and phononic correlations. When the electron-phonon coupling becomes large or the phonon frequency small, the system undergoes a transition to an insulating Peierls phase with a twofold degenerate ground state, long-range charge-density-wave order, a dimerized lattice structure, and a gap in the electronic excitation spectrum.

arXiv:cond-mat/9903149Physical review. B, Condensed matterSep 15, 1999102 citations

Metal-insulator transition in the Hubbard model

R. Bulla, Thomas Pruschke, Alex C. Hewson

Physica B Condensed MatterJan 1, 19999 citations

We have performed extensive density matrix renormalization group (DMRG) studies of the Hubbard model on a honeycomb ladder. The band structure (with Hubbard

U=0

) exhibits an unusual quadratic band touching at half-filling, which is associated with a quantum Lifshitz transition from a band insulator to a metal. For one electron per site, nonzero

U

drives the system into an insulating state in which there is no pair-binding between added electrons; this implies that superconductivity driven directly by the repulsive electron-electron interactions is unlikely in the regime of small doping, $x\ensuremath{\ll}1$. However, the divergent density of states as $x\ensuremath{\rightarrow}0$, the large values of the phonon frequencies, and an unusual correlation induced enhancement of the electron-phonon coupling imply that lightly doped polyacenes, which approximately realize this structure, are good candidates for high-temperature electron-phonon driven superconductivity.

We study the one-dimensional Holstein model with spin-

\frac{1}{2}

electrons at half filling. Ground-state properties are calculated for long chains with great accuracy using the density-matrix renormalization-group method and extrapolated to the thermodynamic limit. We show that for small electron-phonon coupling or large phonon frequency, the insulating Peierls ground state predicted by mean-field theory is destroyed by quantum lattice fluctuations and that the system remains in a metallic phase with a nondegenerate ground state and power-law electronic and phononic correlations. When the electron-phonon coupling becomes large or the phonon frequency small, the system undergoes a transition to an insulating Peierls phase with a twofold degenerate ground state, long-range charge-density-wave order, a dimerized lattice structure, and a gap in the electronic excitation spectrum.