Failed excitonic quantum phase transition in Ta2Ni(Se1−xSx)5
Failed excitonic quantum phase transition in Ta2Ni(Se1−xSx)5
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DOI：
10.1103/physrevb.104.l241103
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发表时间：
2021-04
影响因子：
3.7
通讯作者：
P. Volkov;M. Ye;H. lohani;I. Feldman;A. Kanigel;G. Blumberg
中科院分区：
文献类型：
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作者：
P. Volkov;M. Ye;H. lohani;I. Feldman;A. Kanigel;G. Blumberg
我们使用偏振分辨拉曼光谱研究了激子绝缘体候选物 Ta2Ni(Se1−xSx)5 [x=0, ... ,1] 的电子相图。观察到临界激子涨落，该涨落随 x 减小并最终转变为高能，这是量子相变的特征。尽管如此，在有限温度下，所有 x 都检测到对称破缺转变，从而暴露了大 x 的合作晶格不稳定性。我们的研究揭示了失败的激子量子相变，被先发制人的结构顺序所掩盖。
We study the electronic phase diagram of the excitonic insulator candidates Ta2Ni(Se1−xSx)5 [x=0, ... ,1] using polarization resolved Raman spectroscopy. Critical excitonic fluctuations are observed, that diminish with x and ultimately shift to high energies, characteristic of a quantum phase transition. Nonetheless, a symmetry-breaking transition at finite temperatures is detected for all x, exposing a cooperating lattice instability that takes over for large x. Our study reveals a failed excitonic quantum phase transition, masked by a preemptive structural order.