Uniaxial-Pressure Control of Excitonic Fluctuations and Monoclinic Distortions in Ta2NiSe5

IF 9 1区物理与天体物理 Q1 PHYSICS, MULTIDISCIPLINARY

Physical review letters Pub Date : 2025-10-09 DOI:10.1103/jysr-2dk1

X. Shi, Y.-S. Zhang, D. Huang, M. Isobe, H. Takagi, B. Keimer, A. V. Boris

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引用次数: 0

Abstract

Ta2NiSe5 undergoes a phase transition characterized by the opening of an energy gap and a reduction in its crystal symmetry below Tc=326 K. The primary cause of this transition is debated to be either electron-hole correlations, in line with the excitonic insulator hypothesis, or structural instability. The chain structure of Ta2NiSe5 enables effective control over its electronic and lattice properties by applying uniaxial strain. In this study, we utilize polarization-resolved Raman spectroscopy to demonstrate that the electronic and structural order parameters respond differently to uniaxial pressure applied along the Ta-Ni chains. Compressive strain reduces monoclinic distortions while enhancing excitonic fluctuations. Such disparate behavior suggests that many-body effects may significantly amplify exciton fluctuations even when monoclinic distortions are minimized, thereby supporting the excitonic nature of the phase transition.

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Ta2NiSe5中激子波动和单斜畸变的单轴压力控制

Ta2NiSe5在Tc=326 K以下经历了一个相变，其特征是能隙的打开和晶体对称性的降低。这种转变的主要原因被认为是电子-空穴相关，与激子绝缘体假说一致，或者是结构不稳定。Ta2NiSe5的链状结构可以通过施加单轴应变来有效控制其电子和晶格性质。在这项研究中，我们利用偏振分辨拉曼光谱来证明电子和结构有序参数对沿Ta-Ni链施加的单轴压力有不同的响应。压缩应变减少单斜扭曲，同时增强激子波动。这种不同的行为表明，即使在单斜扭曲最小化的情况下，多体效应也可能显著放大激子波动，从而支持相变的激子性质。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Physical review letters 物理-物理：综合

CiteScore

16.50

自引率

7.00%

发文量

2673

审稿时长

2.2 months

期刊介绍： Physical review letters(PRL)covers the full range of applied, fundamental, and interdisciplinary physics research topics: General physics, including statistical and quantum mechanics and quantum information Gravitation, astrophysics, and cosmology Elementary particles and fields Nuclear physics Atomic, molecular, and optical physics Nonlinear dynamics, fluid dynamics, and classical optics Plasma and beam physics Condensed matter and materials physics Polymers, soft matter, biological, climate and interdisciplinary physics, including networks