Crossover from metal to insulator in dense lithium-rich compound CLi 4

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 113; no. 9; pp. 2366 - 2369
• Main Authors: Jin, Xilian, Chen, Xiao-Jia, Cui, Tian, Mao, Ho-kwang, Zhang, Huadi, Zhuang, Quan, Bao, Kuo, Zhou, Dawei, Liu, Bingbing, Zhou, Qiang, He, Zhi
• Format: Journal Article
• Language: English
• Published: 01.03.2016
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1525412113

The binary compound researched here enriches the studies of antimetallization just like in the pure elemental system, and the fundamental nature of matter in the subject has been expanded. During metallizing or antimetallizing in metallic states, the Fermi surface filling parameter is found to be a valuable parameter to quantify the evolution of the free electrons. At room environment, all materials can be classified as insulators or metals or in-between semiconductors, by judging whether they are capable of conducting the flow of electrons. One can expect an insulator to convert into a metal and to remain in this state upon further compression, i.e., pressure-induced metallization. Some exceptions were reported recently in elementary metals such as all of the alkali metals and heavy alkaline earth metals (Ca, Sr, and Ba). Here we show that a compound of CLi 4 becomes progressively less conductive and eventually insulating upon compression based on ab initio density-functional theory calculations. An unusual path with pressure is found for the phase transition from metal to semimetal, to semiconductor, and eventually to insulator. The Fermi surface filling parameter is used to describe such an antimetallization process.