AI 中文总结
该研究通过密度泛函理论将压力诱导的金属-绝缘体转变分为三类，提出类金属键作为潜在成键机制，用量子化学描述符捕捉成键变化，揭示了不同类型固体在MIT处的性质差异。
AI 中文摘要
压力诱导的金属-绝缘体转变（MIT）通过密度泛函理论计算得到的特征光电性质和振动性质的演化进行分类，形成三类：离子固体在带隙闭合时连续金属化，声子硬化；共价固体表现出原子排列和光学声子频率的不连续变化；第三类表现出完全的晶格软化和电子-声子耦合的显著增强。一维氢链可重现该行为，作为潜在成键机制的玩具模型，称为类金属键。两个量子化学描述符可捕捉三类背后的不同成键变化：类金属固体中，电子的竞争局域化与离域化在绝缘侧产生软光学模式和佩尔斯畸变，在金属侧产生超导性，在MIT附近呈现低晶格热导率。
英文摘要
Pressure induced metal insulator transitions (MIT) are classified by the evolution of characteristic optoelectronic and vibrational properties calculated with density functional theory. Three classes emerge: ionic solids metallize continuously at band-gap closure with hardening phonons; covalent solids show discontinuous changes in atomic arrangement and optical phonon frequencies; a third class exhibits complete lattice softening and drastically enhanced electron phonon coupling. A one dimensional hydrogen chain reproduces this behavior and serves as a toy model of the underlying bonding mechanism, termed metavalent. Two quantum-chemical descriptors capture the distinct bonding changes behind the three classes. In metavalent solids, competing electron localization and delocalization yield soft optical modes and Peierls distortions on the insulating side, superconductivity on the metallic side, and low lattice thermal conductivity near the MIT.
