Murase Hideaki, Arai Shunto, Hasegawa Tatsuo, Miyagawa Kazuya, Kanoda Kazushi
Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Research Center for Macromolecules and Biomaterials, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0044, Japan.
Nat Commun. 2023 Sep 26;14(1):6011. doi: 10.1038/s41467-023-41731-7.
Liquids crystallize as they cool; however, when crystallization is avoided in some way, they supercool, maintaining their liquidity, and freezing into glass at low temperatures, as ubiquitously observed. These metastable states crystallize over time through the classical dynamics of nucleation and growth. However, it was recently found that Coulomb interacting electrons on charge-frustrated triangular lattices exhibit supercooled liquid and glass with quantum nature and they crystallize, raising fundamental issues: what features are universal to crystallization at large and specific to that of quantum systems? Here, we report our experimental challenges that address this issue through the spatiotemporal observation of electronic crystallization in an organic material. With Raman microspectroscopy, we have successfully performed real-space and real-time imaging of electronic crystallization. The results directly capture strongly temperature-dependent crystallization profiles indicating that nucleation and growth proceed at distinctive temperature-dependent rates, which is common to conventional crystallization. However, the growth rate is many orders of magnitude larger than that in the conventional case. The temperature characteristics of nucleation and growth are universal, whereas unusually fast growth kinetics features quantum crystallization where a quantum-to-classical catastrophe occurs in interacting electrons.
液体冷却时会结晶；然而，当以某种方式避免结晶时，它们会过冷，保持其流动性，并在低温下冻结成玻璃态，这是普遍观察到的现象。这些亚稳态会随着时间通过成核和生长的经典动力学过程而结晶。然而，最近发现，电荷受挫的三角晶格上的库仑相互作用电子表现出具有量子性质的过冷液体和玻璃态，并且它们会结晶，这引发了一些基本问题：结晶在宏观上有哪些普遍特征，而在量子系统中又有哪些特定特征？在这里，我们报告了我们通过对一种有机材料中的电子结晶进行时空观测来解决这个问题所面临的实验挑战。利用拉曼显微光谱，我们成功地对电子结晶进行了实空间和实时成像。结果直接捕捉到了强烈依赖温度的结晶轮廓，表明成核和生长以与温度相关的独特速率进行，这在传统结晶中是常见的。然而，生长速率比传统情况大许多个数量级。成核和生长的温度特性是普遍的，而异乎寻常的快速生长动力学则是量子结晶的特征，在相互作用的电子中会发生量子到经典的转变。
