Predicted novel insulating electride compound between alkali metals lithium and sodium under high pressure

• 来源期刊: 中国物理B（英文版）
• 关键词: high pressure structure prediction alkali metals
• 年，卷（期）: 2017,（5）
• 页码范围: 293-298
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/26/5/056102

摘要

The application of high pressure can fundamentally modify the crystalline and electronic structures of elements as well as their chemical reactivity,which could lead to the formation of novel materials.Here,we explore the reactivity of lithium with sodium under high pressure,using a swarm structure searching techniques combined with first-principles calculations,which identify a thermodynamically stable Li-Na compound adopting an orthorhombic oP8 phase at pressure above 355 GPa.The formation of Li-Na may be a consequence of strong concentration of electrons transfering from the lithium and the sodium atoms into the interstitial sites,which also leads to open a relatively wide band gap for LiNaoP8.This is substantially different from atoms sharing or exchanging electrons in common compounds and alloys.In addition,lattice-dynamic calculations indicate that LiNa-oP8 remains dynamically stable when pressure decompresses down to 70 GPa.