Charge-order transition in the extended Hubbard model on a two-leg ladder
Charge-order transition in the extended Hubbard model on a two-leg ladder
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两腿梯上扩展哈伯德模型中的电荷顺序转换
DOI：
10.1103/physrevb.60.r8417
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发表时间：
1999
影响因子：
3.7
通讯作者：
R. Noack
中科院分区：
文献类型：
--
作者：
M. Vojta;R. Hetzel;R. Noack
我们使用密度矩阵重正化群技术研究了具有附加最近邻库仑斥力 $V$ 的两腿哈伯德梯子中零温度下的电荷顺序转变。我们考虑四分之一填充和一半填充之间的电子密度。对于四分之一填充和$U=8t，$我们发现了小$V$的均匀状态和具有“棋盘”[波向量$\mathbf{Q}=(\ensuremath{\pi},\ensuremath{\pi})$]大$V的电荷顺序的破缺对称状态之间连续相变的证据。$这种转变到棋盘格 电荷有序状态在所有较大的填充物中仍然存在，但在足够大的填充物中变得不连续。我们讨论 $U/t$ 对转变的影响并估计三临界点的位置。
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.