Discovery of dynamical heterogeneity in a supercooled magnetic monopole fluid

• 成果类型: Article
• 署名作者: Dasini, Jahnatta; Carroll, Chaia; Murphy, Jack; Dawson, Catherine; Takahashi, Hiroto; Sharma, Sudarshan; Jerzembeck, Fabian; Blundell, Stephen J.; Luke, Graeme M.; Davis, J. C. Seamus; Ward, Jonathan
• 署名单位: University College Cork; University of Oxford; McMaster University; Max Planck Society
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2528457123
• 发表日期: 2026-06-09
• 页码: e2528457123
• 关键词: vitrification; dynamical heterogeneity; SUPERCOOLED LIQUIDS; spin-ice; emergent magnetic monopoles; glass-transition; SPIN ICE; relaxation; liquids

摘要

Dynamical heterogeneity, in which transitory local fluctuations occur in the conformation and dynamics of constituent particles, is widely hypothesized to be essential to the evolution of supercooled liquids into the structural glass state. Yet its microscopic spatiotemporal phenomenology is challenging to detect directly in molecular glass forming liquids. Because recent theoretical advances predict that corresponding dynamical heterogeneity could occur in supercooled magnetic monopole fluids (Proc. Nat. Acad. Sci. 112, 8549 (2015)), we searched for such phenomena in Dy2Ti2O7. By measuring its microsecond-resolved spontaneous magnetization fluctuations M(t,T) we detected a sharp bifurcation in monopole noise characteristics below T approximate to 1,500 mK, with the appearance of powerful spontaneous monopole current bursts. This intense dynamics emerges upon entering the supercooled monopole fluid regime, reaches maximum strength near T approximate to 750 mK and then collapses along with coincident loss of ergodicity approaching Tg approximate to 250 mK. Moreover, when the four-point dynamical susceptibility chi 4(tau,T) is determined directly from temperature dependence of correlations in M(t,T), it evolves as predicted when dynamical heterogeneity is present, revealing its simultaneously and rapidly escalating length and time scales, xi(T) and tau 4(T). This overall phenomenology greatly expands our empirical knowledge of supercooled monopole fluids and, more generally, demonstrates techniques for detection of the time sequence, magnitude, statistics, and correlations of dynamical heterogeneity, access to which may greatly accelerate fundamental vitrification studies.