激子绝缘体 Ta$_2$NiSe$_5$ 结构相变中的声子软模与强电子背景行为（含勘误）
摘要
TaNiSe 已成为最受关注的激子绝缘体基态候选材料之一。许多研究将该相变描述为使连续对称性破缺的激子凝聚。近来这一观点受到挑战，研究指出在半导体–激子绝缘体相变同时发生的结构相变中，两个镜面对称性的丧失具有重要意义。针对此种情形，有研究提出由低能不稳定光学区中心声子驱动该相变。本文报道利用拉曼光谱对这种软模行为的实验观测。此外，我们发现一种新颖的谱学特征，其可能源于电子或电子与声子联合机制，明显区别于晶格动力学，并在 Tc 处占据主导。这表明结构序与电子序联合驱动相变的图景。
引用
@article{arxiv.2007.01723,
title = {Phononic soft mode and strong electronic background behavior across the structural phase transition in the excitonic insulator Ta$_2$NiSe$_5$ (with Erratum)},
author = {Min-Jae Kim and Armin Schulz and Tomohiro Takayama and Masahiko Isobe and Hidenori Takagi and Stefan Kaiser},
journal= {arXiv preprint arXiv:2007.01723},
year = {2021}
}
备注
Merged version with Erratum (1 page) in the original manuscript (21 pages, 8 figures). After publication of [Phys. Rev. Research 2, 042039 (2020), arXiv:2007.01723v2] [1] we got notified on an instrumental artifact in the low frequency part of the Raman spectrum of Ta$_2$NiSe$_5$. This erroneously led to a description of a soft phonon mode and a strong electronic background. Properly taking into account a low frequency electronic signal correctly explains the observed soft mode as Fano coupled phonon where a critical softening of an excitonic collective mode takes place as described by P.A. Volkov et al. in arXiv:2007.07344 [2] and M. Ye et al. in arXiv:2102.07912 [3]