发表机构
University of Virginia（弗吉尼亚大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过模拟二维准经典Holstein模型中的CDW粗化，发现微观电荷守恒导致畴壁运动受限，产生介于1/4和1/2之间的表观生长指数，并由交叉动力学解释，揭示了非守恒序参量下守恒律驱动的异常粗化机制。
AI 中文摘要
我们研究了二维准经典Holstein模型中热淬火进入有序相后的电荷密度波（CDW）粗化过程。尽管交错CDW序参量是非守恒的，畴壁运动仍受微观电子电荷守恒的约束。模拟显示出介于$1/4$和Allen-Cahn值$1/2$之间的表观生长指数。这些表观指数主要由交叉动力学$\n\ndot{L}=[D(T)/L][1+L_\times^2(T)/L^2]$解释，其中$L_\times(T)$是温度依赖的交叉长度。在低温下，近乎二元的占据要求相容的壁段协同重排，产生$L(t)\sim t^{1/4}$的极限。热展宽创造了部分占据的界面位点，允许局域曲率驱动的运动，并在后期恢复$L(t)\sim t^{1/2}$。对测量生长速率、无量纲速率塌缩以及长时间大系统模拟的拟合一致支持这一交叉图像。这些结果表明，即使涌现的序参量是非守恒的，微观守恒律也能产生长寿命的异常粗化。
英文摘要
We investigate charge-density-wave (CDW) coarsening in a two-dimensional quasiclassical Holstein model following thermal quenches into the ordered phase. Although the staggered CDW order parameter is nonconserved, domain-wall motion remains constrained by conservation of the microscopic electronic charge. The simulations exhibit apparent growth exponents between $1/4$ and the Allen--Cahn value $1/2$. These apparent exponents are primarily accounted for by the crossover kinetics $\dot{L}=[D(T)/L][1+L_\times^2(T)/L^2]$, where $L_\times(T)$ is a temperature-dependent crossover length. At low temperature, nearly binary occupations require compatible wall segments to rearrange cooperatively, producing the $L(t)\sim t^{1/4}$ limit. Thermal broadening creates partially occupied interfacial sites that permit local curvature-driven motion and restore $L(t)\sim t^{1/2}$ at late times. Fits to the measured growth rate, a dimensionless rate collapse, and a long-time large-system simulation consistently support this crossover picture. These results show that a microscopic conservation law can generate long-lived anomalous coarsening even when the emergent order parameter is nonconserved.
Comments13 pages, 8 figures
