AI 中文总结
针对稀土三碲化物的Te方格网平面构建二维电声子模型，经平均场分析发现其单向CDW相存在镜对称性破缺的固有敏感性，为理解相关实验提供了理论依据。
AI 中文摘要
尽管稀土三碲化物（$R$Te$_3$）被认为是最简单且表征最充分的准二维电荷密度波（CDW）系统，但仍不断产生令人惊讶的实验结果，包括近期与CDW序开始相关的镜对称性破缺的证据。受此启发，我们针对单个Te方格网平面构建了二维电声子模型，并使用平均场理论对其进行分析。在参数空间的合适区域，我们发现从正常态到单向CDW态存在有限温度的连续相变，其有序波矢与实验观测结果匹配。在更低温度下，我们发现第二次平移对称性破缺相变，与重稀土元素的$R$Te$_3$化合物中发生的情况类似。在某些参数范围内，我们还发现在上述两次相变之间存在中间的镜对称性破缺相变。这些结果揭示了单向CDW相具有镜对称性破缺的固有 susceptibility（敏感性），这与理解$R$Te$_3$化合物的近期实验相关。
英文摘要
Despite being arguably the simplest and best characterized quasi-2D charge-density-wave (CDW) systems, the rare-earth tritellurides ($R$Te$_3$) continue to yield surprising experimental results, including recent evidence suggestive of mirror-symmetry breaking associated with the onset of CDW order. Motivated by this, we consider a 2D electron-phonon model for a single Te square-net plane, which we analyze using mean-field theory. For an appropriate region of parameter space, we find a finite-temperature continuous transition from the normal state to a unidirectional CDW state with an ordering vector matching that observed experimentally. At lower temperatures, we find a second translation-symmetry-breaking transition, similar to what occurs in $R$Te$_3$ compounds with heavier rare-earth elements. In certain parameter regimes, we also find an intervening mirror-symmetry-breaking transition occurring between the two transitions described above. These results reveal an intrinsic susceptibility to mirror-symmetry breaking in the unidirectional CDW phase, which is relevant to understanding recent experiments on the $R$Te$_3$ compounds.
Comments8 pages, 5 figures, plus Supplemental Material
