We investigate the charge-order transition at zero temperature in a two-leg Hubbard ladder with additional nearest-neighbor Coulomb repulsion $V$ using the density matrix renormalization group technique. We consider electron densities between quarter and half filling. For quarter filling and $U=8t,$ we find evidence for a continuous phase transition between a homogeneous state at small $V$ and a broken-symmetry state with ``checkerboard'' [wave vector $\mathbf{Q}=(\ensuremath{\pi},\ensuremath{\pi})$] charge order at large $V.$ This transition to a checkerboard charge-ordered state remains present at all larger fillings, but becomes discontinuous at sufficiently large filling. We discuss the influence of $U/t$ on the transition and estimate the position of the tricritical points.We investigate the charge-order transition at zero temperature in a two-leg Hubbard ladder with additional nearest-neighbor Coulomb repulsion $V$ using the density matrix renormalization group technique. We consider electron densities between quarter and half filling. For quarter filling and $U=8t,$ we find evidence for a continuous phase transition between a homogeneous state at small $V$ and a broken-symmetry state with ``checkerboard'' [wave vector $\mathbf{Q}=(\ensuremath{\pi},\ensuremath{\pi})$] charge order at large $V.$ This transition to a checkerboard charge-ordered state remains present at all larger fillings, but becomes discontinuous at sufficiently large filling. We discuss the influence of $U/t$ on the transition and estimate the position of the tricritical points.

arXiv:cond-mat/9906101Physical review. B, Condensed matterSep 15, 199934 citations

Orbital currents and charge density waves in a generalized Hubbard ladder

John Ove Fjærestad, John Bradley Marston, Ulrich Schollwöck

arXiv:cond-mat/0412709Annals of PhysicsNov 3, 200513 citations

Aspects of the ground state of the U=∞ Hubbard ladder

Masanori Kohno

We consider two aspects of the ground state of the $U=\ensuremath{\infty}$ Hubbard ladder: ferromagnetism and the metal-insulator transition at quarter-filling. First, we present rigorous results for the $U=\ensuremath{\infty}$ Hubbard ladder in the limit of the large interchain hopping ${(t}_{\ensuremath{\perp}}/t\ensuremath{\rightarrow}\ensuremath{\infty})$. In this limit, the total spin $S$ of the ground state is shown to be zero for the electron density $n<~0.5$ and its maximum ${(S=S}_{\mathrm{max}})$ for $n>0.5$ . The charge gap at quarter-filling is ${2t}_{\ensuremath{\perp}}.$ We extend these results to finite ${t}_{\ensuremath{\perp}}/t$ by means of the density-matrix renormalization group method. We estimate the phase boundaries with respect to spontaneous magnetization and the charge gap at quarter-filling for finite ${t}_{\ensuremath{\perp}}/t$. Applying the extended Aharonov-Bohm method, we give numerical evidence that the critical ratio ${t}_{\ensuremath{\perp}}/t$, above which the charge gap opens, is less than 0.001. Ferromagnetism in the $t$ - $J$ ladder is briefly discussed.We consider two aspects of the ground state of the $U=\ensuremath{\infty}$ Hubbard ladder: ferromagnetism and the metal-insulator transition at quarter-filling. First, we present rigorous results for the $U=\ensuremath{\infty}$ Hubbard ladder in the limit of the large interchain hopping ${(t}_{\ensuremath{\perp}}/t\ensuremath{\rightarrow}\ensuremath{\infty})$. In this limit, the total spin $S$ of the ground state is shown to be zero for the electron density $n<~0.5$ and its maximum ${(S=S}_{\mathrm{max}})$ for $n>0.5$. The charge gap at quarter-filling is ${2t}_{\ensuremath{\perp}}.$ We extend these results to finite ${t}_{\ensuremath{\perp}}/t$ by means of the density-matrix renormalization group method. We estimate the phase boundaries with respect to spontaneous magnetization and the charge gap at quarter-filling for finite ${t}_{\ensuremath{\perp}}/t$. Applying the extended Aharonov-Bohm method, we give numerical evidence that the critical ratio ${t}_{\ensuremath{\perp}}/t$, above which the charge gap opens, is less than 0.001. Ferromagnetism in the $t$-$J$ ladder is briefly discussed.

arXiv:cond-mat/9709170Physical review. B, Condensed matterDec 15, 199726 citations

Regular density waves in the half filled 1D extended Hubbard model with a bond alternation

Norikazu Tomita, Hideo Fukutome

Solid State CommunicationsFeb 1, 19927 citations

Creation and Destruction of a Spin Gap in Weakly Coupled Quarter-Filled Ladders

Bernhard Edegger, Hans Gerd Evertz, R. M. Noack

We investigate weakly coupled quarter-filled ladders with model parameters relevant for NaV(2)O(5) using density-matrix renormalization group calculations on an extended Hubbard model coupled to the lattice. NaV(2)O(5) exhibits super-antiferroelectric charge order with a zigzag pattern on each ladder. We show that this order causes a spin dimerization along the ladder and is accompanied by a spin gap of the same magnitude as that observed experimentally. The spin gap is destroyed again at large charge order due to a restructuring of the spins. An analysis of an effective spin model predicts a recreation of the gap by interladder singlets when the charge order increases further.We investigate weakly coupled quarter-filled ladders with model parameters relevant for NaV(2)O(5) using density-matrix renormalization group calculations on an extended Hubbard model coupled to the lattice. NaV(2)O(5) exhibits super-antiferroelectric charge order with a zigzag pattern on each ladder. We show that this order causes a spin dimerization along the ladder and is accompanied by a spin gap of the same magnitude as that observed experimentally. The spin gap is destroyed again at large charge order due to a restructuring of the spins. An analysis of an effective spin model predicts a recreation of the gap by interladder singlets when the charge order increases further.

arXiv:cond-mat/0510325Physical Review LettersApr 12, 20067 citations

Study of Charge Density Wave Modulations in the Extended Hubbard Model

Saumya Biswas, Roger K. Lake

Bulletin of the American Physical SocietyMar 3, 20150 citations

We investigate the charge-order transition at zero temperature in a two-leg Hubbard ladder with additional nearest-neighbor Coulomb repulsion

V

using the density matrix renormalization group technique. We consider electron densities between quarter and half filling. For quarter filling and

U=8t,

we find evidence for a continuous phase transition between a homogeneous state at small

V

and a broken-symmetry state with ``checkerboard'' [wave vector $\mathbf{Q}=(\ensuremath{\pi},\ensuremath{\pi})$] charge order at large

V.

This transition to a checkerboard charge-ordered state remains present at all larger fillings, but becomes discontinuous at sufficiently large filling. We discuss the influence of

U/t

on the transition and estimate the position of the tricritical points.

S

of the ground state is shown to be zero for the electron density

n<~0.5

and its maximum

{(S=S}_{\mathrm{max}})

for

n>0.5

. The charge gap at quarter-filling is ${2t}_{\ensuremath{\perp}}.$ We extend these results to finite ${t}_{\ensuremath{\perp}}/t$ by means of the density-matrix renormalization group method. We estimate the phase boundaries with respect to spontaneous magnetization and the charge gap at quarter-filling for finite ${t}_{\ensuremath{\perp}}/t$. Applying the extended Aharonov-Bohm method, we give numerical evidence that the critical ratio ${t}_{\ensuremath{\perp}}/t$, above which the charge gap opens, is less than 0.001. Ferromagnetism in the

t

J

ladder is briefly discussed.