Pressure-induced novel structure with graphene-like boron-layer in titanium monoboride  

作　　者：Yuan-Yuan Jin Jin-Quan Zhang Shan Ling Yan-Qi Wang Song Li Fang-Guang Kuang Zhi-Yan Wu Chuan-Zhao Zhang 金园园;张金权;凌山;王妍琪;李松;匡芳光;武志燕;张传钊(Department of Physics and Optoelectronic Engineering,Yangtze University,Jingzhou 434023,China;School of Physics and Electronic Information,Gannan Normal University,Ganzhou 341000,China;College of Electronic and Electrical Engineering,Henan Normal University,Xinxiang 453007,China)

机构地区：[1]Department of Physics and Optoelectronic Engineering,Yangtze University,Jingzhou 434023,China [2]School of Physics and Electronic Information,Gannan Normal University,Ganzhou 341000,China [3]College of Electronic and Electrical Engineering,Henan Normal University,Xinxiang 453007,China

出　　处：《Chinese Physics B》2022年第11期416-423,共8页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.11804031);the Scientific Research Project of Education Department of Hubei Province,China(Grant No.Q20191301);Youth Science Foundation of Jiangxi Province,China(Grant No.20171BAB211009);Henan Province Key Research and Development and Promotion of Special Scientific and Technological Research Project(Grant No.222102320283)。

摘　　要：The recent discovery of the novel boron-framework in boron-rich metal borides with complex structures and intriguing features under high pressure has stimulated the search into the unique boron-network in the metal monoborides or boron-deficient metal borides at high pressure.Herein,based on the particle swarm optimization algorithm combined with first-principles calculations,we thoroughly explored the structural evolution and properties of TiB up to 200 GPa.This material undergoes a pressure-induced phase transition of Pnma→Cmcm→Pmmm.Besides of two known phases Pnma and Cmcm,an unexpected orthorhombic Pmmm structure was predicted to be energetically favored in the pressure range of 110.88–200 GPa.Intriguingly,the B covalent network eventually evolved from a one-dimensional zigzag chain in Pnma-TiB and Cmcm-TiB to a graphene-like B-sheet in Pmmm-TiB.On the basis of the microscopic hardness model,the calculated hardness(H_(v))values of Pnma at 1 atm,Cmcm at 100 GPa,and Pmmm at 140 GPa are 36.81 GPa,25.17 GPa,and15.36 GPa,respectively.Remarkably,analyses of the density of states,electron localization function and the crystal orbital Hamilton population(COHP)exhibit that the bonding nature in the three TiB structures can be considered as a combination of the B–B and Ti–B covalent interactions.Moreover,the high hardness and excellent mechanical properties of the three Ti B polymorphs can be ascribed to the strong B–B and Ti–B covalent bonds.

关 键 词：transition-metal boride high pressure FIRST-PRINCIPLES phase transition 

分 类 号：TB30[一般工业技术—材料科学与工程]