内嵌富勒烯锯齿链中的量子相

中文摘要 AI 辅助

我们采用大规模密度矩阵重整化群计算，研究了受限在弯曲（锯齿形）内嵌富勒烯链中的偶极分子的量子相，作为链角γ的函数。对于LiF，铁电序在60°<γ<180°的整个范围内持续存在，临界有效偶极矩随着链的弯曲而增加，平行排列变得不那么有利。在等边构型（γ = 60°）附近，几何失稳驱动向反铁电尼尔有序相的转变，其中相邻偶极沿链轴反平行排列。我们表明，捕捉这种重新取向需要包括超出最近邻近似的偶极耦合，因为次近邻相互作用在γ = 60°时变得同样强。对于受限水，邻-重水重现了两个有序相，而对-重水——由于其大的转动常数——尽管弯曲几何结构增强了配位，但在任何链角都没有形成有序。由于锯齿链是二维晶格中最窄的条带，这些结果表明，工程化的内嵌富勒烯层可以承载除先前工作中观察到的铁电序之外的丰富多样的偶极有序量子相。

英文摘要

We employ large-scale density matrix renormalization group calculations to study the quantum phases of dipolar molecules confined in bent (zigzag) endofullerene chains, as a function of the chain angle $γ$. For LiF, ferroelectric order persists across the full range $60^\circ < γ180^\circ$, with the critical effective dipole moment increasing as the chain bends and parallel alignment becomes less favorable. Near the equilateral configuration ($γ= 60^\circ$), geometric frustration drives a transition to an antiferroelectric Néel-ordered phase in which neighboring dipoles anti-align along the chain axis. We show that capturing this reorientation requires including dipolar couplings beyond the nearest-neighbor approximation, since next-nearest-neighbor interactions become equally strong at $γ= 60^\circ$. For confined water, o-D$_2$O reproduces both ordered phases, whereas p-H$_2$O -- owing to its large rotational constants -- develops no order at any chain angle despite the enhanced coordination of the bent geometry. Because a zigzag chain is the narrowest stripe of a two-dimensional lattice, these results suggest that engineered endofullerene layers could host a rich variety of dipole-ordered quantum phases beyond the ferroelectric ordering observed in previous work.

补充信息

备注

4 figures