Pressure- driven electronegativity inversion in alkali liquids

• 成果类型: Article
• 署名作者: Han, Chenxu; Zong, Hongxiang; Ding, Xiangdong; Sun, Jun; Ackland, Graeme J.
• 署名单位: Xi'an Jiaotong University; University of Edinburgh
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9417
• DOI: 10.1073/pnas.2424701122
• 发表日期: 2025-07-01
• 关键词: phase-transition; electrides

摘要

Liquid-liquid phase transitions (LLPTs) are typically characterized as two-state systems, where transitions occur between two distinct liquid phases driven by local structural rearrangements. In this study, we observed a continuous LLPT with an inversion of electronegativity in a K-Rb binary alloy. This uniquely exhibits a three-state system behavior. The transition, induced by pressure-driven reordering of electronic orbital energies, progresses through a sequence from s-metal to electride to ti-metal, accompanied by a valence reversal: Potassium transitions from a negative to a positive valence, while rubidium undergoes the opposite shift. This process is marked by two successive anomalies in the alloy's optical, thermodynamic, and dynamic properties over a broad pressure range. The observation of similar LLPT phenomena in other alkali and alkaline earth metal liquids suggests that this three-state system mechanism may provide broader insights into the nature of continuous phase transitions.