近日，美国内华达大学Thomas G. White团队揭示了过热的黄金超过了预测的熵突变阈值。2025年7月23日，《自然》杂志发表了这一成果。

在此前一项里程碑式的研究中，费希特和约翰逊揭示了一种被他们称为“熵变”的现象，即过热晶体的熵与液体晶体的熵相等的临界点。这一点标志着固体在其熔点的三倍左右的温度下的最高稳定边界。尽管理论上预测了这个最终的稳定阈值，但它的实际探索却受到许多中间不稳定事件的阻碍，这些事件通常被称为发生在低得多的温度下的灾难等级。

研究组在超快加热条件下实验测试了这一极限，通过主题化高分辨率非弹性x射线散射直接跟踪晶格温度。他们的金样品被加热到超过熔点14倍的温度，同时保留了它们的晶体结构，远远超过了预测的阈值，这表明过热的限制要高得多，或者可能没有限制。研究组指出，他们的样本无法在这些非常短的时间尺度上扩展，这是与以前估计的一个重要区别。这些观测提供了对极端条件下融化动力学的见解。

附：英文原文

Title: Superheating gold beyond the predicted entropy catastrophe threshold

Author: White, Thomas G., Griffin, Travis D., Haden, Daniel, Lee, Hae Ja, Galtier, Eric, Cunningham, Eric, Khaghani, Dimitri, Descamps, Adrien, Wollenweber, Lennart, Armentrout, Ben, Convery, Carson, Appel, Karen, Fletcher, Luke B., Goede, Sebastian, Hastings, J. B., Iratcabal, Jeremy, McBride, Emma E., Molina, Jacob, Monaco, Giulio, Morrison, Landon, Stramel, Hunter, Yunus, Sameen, Zastrau, Ulf, Glenzer, Siegfried H., Gregori, Gianluca, Gericke, Dirk O., Nagler, Bob

Issue&Volume: 2025-07-23

Abstract: In their landmark study1, Fecht and Johnson unveiled a phenomenon that they termed the ‘entropy catastrophe’, a critical point where the entropy of superheated crystals equates to that of their liquid counterparts. This point marks the uppermost stability boundary for solids at temperatures typically around three times their melting point. Despite the theoretical prediction of this ultimate stability threshold, its practical exploration has been prevented by numerous intermediate destabilizing events, colloquially known as a hierarchy of catastrophes2,3,4,5, which occur at far lower temperatures. Here we experimentally test this limit under ultrafast heating conditions, directly tracking the lattice temperature by using high-resolution inelastic X-ray scattering. Our gold samples are heated to temperatures over 14 times their melting point while retaining their crystalline structure, far surpassing the predicted threshold and suggesting a substantially higher or potentially no limit for superheating. We point to the inability of our samples to expand on these very short timescales as an important difference from previous estimates. These observations provide insights into the dynamics of melting under extreme conditions.

DOI: 10.1038/s41586-025-09253-y

Source: https://www.nature.com/articles/s41586-025-09253-y