New ultra-incompressible phases of NbB₄ predicted from first principles

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• 作者：Xiao-Feng Li^a ; Li-Gang Han^a ; Yunshan Hou^b ; Haiyan Yan^c ; Zi-Yu Hu^d ; ^{huziyu@csrc.ac.cn} ; Sheng-Li Zhang^e ; ^{zhangslvip@njust.edu.cn}
• 关键词：First-principles ; Electronic structure ; Transition metal borides
• 刊名：Physics Letters A
• 出版年：2017
• 出版时间：30 January 2017
• 年：2017
• 卷：381
• 期：4
• 页码：362-367
• 全文大小：1622 K
• 卷排序：381

文摘

For the first time, novel superhard phase C2/cC2/c at 0 GPa and Amm2 phase at high pressure of NbB4 are found, which have a structural unit NbB12 polyhedron. The phase transition pressures from phase C2/cC2/c to Amm2 are 42 GPa. Phonon-dispersion calculations and elastic constants show that the structures are dynamically and mechanically stable at ambient condition. Two phases of NbB4 are ultra-incompressible phases.