激子绝缘体相Ta2Pd3Te5中相干声子振幅模式寿命的非凡增强
Extraordinary Lifetime Enhancement of Coherent Phonon-Amplitude Modes in the Excitonic Insulator Phase of Ta2Pd3Te5
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中文总结 AI 辅助
该研究通过相干声子振幅响应表征Ta2Pd3Te5的激子凝聚，发现TC以下声子模式寿命异常增强，并确立为激子凝聚的新指纹，提出极化子耦合与唯象模型解释其机制。
中文摘要 AI 辅助
激子绝缘体（EI）是凝聚激子的一种电子相。然而，在许多原型材料中，伴随的结构转变的存在使有序态纯电子起源的识别复杂化。在此，我们研究了Ta2Pd3Te5，其中EI相在TC ~ 100 K以下发展，且未检测到结构转变。我们通过其相干声子振幅响应来表征激子凝聚体。最引人注目的是，这些模式的寿命增强在TC以下异常强烈地出现，我们将其确立为与激子凝聚相关的一个新的且稳健的指纹。我们讨论了在考虑激子与晶格效应耦合（与耦合声子振幅响应一致）时捕捉这种增强的可能性。在序参量极化子图像中，与激子态的耦合可能修饰声子模式，从而抑制其弛豫；一个唯象模型结合了非谐声子响应以及由于EI相中能隙打开而导致的电子散射减少。
英文摘要
The excitonic insulator (EI) is an electronic phase of condensed excitons. However, in many prototypical materials the presence of a concurrent structural transition complicates the identification of a purely electronic origin of the ordered state. Here, we investigate Ta2Pd3Te5, in which an EI phase develops below TC ~ 100 K in the absence of a detectable structural transition. We characterize the excitonic condensate via its coherent phonon-amplitude response. Most strikingly, an extraordinarily strong lifetime enhancement of these modes sets in below TC which we establish as a new and robust fingerprint linked to exciton condensation. We discuss possibilities to capture the enhancement when taking into account a coupling of excitonic and lattice effects in line with the coupled phonon-amplitude response. Within an order-parameter polaron picture coupling to the excitonic state may dress the phonon mode and thereby suppress its relaxation and a phenomenological model combines the anharmonic phonon response and a reduced electronic scattering due to the gap opening in the EI phase.
发表机构
- Technische Universität Dresden（德累斯顿工业大学）
- Max Planck Institute for Chemical Physics of Solids（马克斯·普朗克固体化学物理研究所）
- Korea Institute of Science and Technology（韩国科学技术院）
- University of Cologne（科隆大学）
机构由 AI 辅助整理，请以论文原文为准。
