Low‐temperature condensation thermodynamics is a fundamental research in the field of condensed matter physics. Prior studies have extensively explored the exciton condensation of indirect‐bandgap semiconductors like silicon (Si) and germanium (Ge), which predominantly focus on temperature effects but neglect the relationship between the initial condensed state and the external excitation power density. Here, based on pure diamond, the impact of excitation power density on condensed‐state thermodynamics is analyzed. With power density as a key variable, an inter‐dependency among exciton, electron–hole plasma, and electron–hole droplets can be observed in diamond. For instance, as the average excitation power density increases (6.15 to 246 mW cm−2), the exciton emission quenching temperature rises from 60 to 120 K. This is because the variation in initial states of the excitonic condensed phase under different excitation power densities leads to the changes in quenching energy, which subsequently affects the temperature dependence of the exciton quenching. This study pioneers a novel approach to explore luminescent thermodynamics in indirect‐bandgap semiconductors with both excitation power density and temperature considered as dimensions simultaneously.

中文翻译：

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纯金刚石中的激子热力学


低温凝聚热力学是凝聚态物理学领域的一项基础研究。以前的研究已经广泛探索了硅 （Si） 和锗 （Ge） 等间接带隙半导体的激子凝聚，它们主要关注温度效应，但忽略了初始凝聚态与外部激发功率密度之间的关系。在这里，以纯金刚石为基础，分析了激发功率密度对凝聚态热力学的影响。以功率密度为关键变量，可以在金刚石中观察到激子、电子-空穴等离子体和电子-空穴液滴之间的相互依赖性。例如，随着平均激发功率密度的增加（6.15 至 246 mW cm−2），激子发射猝灭温度从 60 K 上升到 120 K。这是因为在不同激发功率密度下，激子凝聚相初始状态的变化导致猝灭能的变化，进而影响激子猝灭的温度依赖性。本研究开创了一种探索间接带隙半导体中发光热力学的新方法，同时将激发功率密度和温度视为维度。