Mixed-metal effects on ultra-incompressible metal diborides: Density functional computations

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• 作者：Fei Lin ; Kechen Wu ; Jiangang He ; Rongjian Sa ; Qiaohong Li ; Yongqin Wei
• 刊名：Chemical Physics Letters
• 出版年：2010
• 出版时间：9 July 2010
• 年：2010
• 卷：494
• 期：1-3
• 页码：31-36
• 全文大小：814 K

文摘

Mixed-metal borides are promising superhard materials (Kaner et al. (2005) [1]). In this Letter, density functional computations have been applied to the structural, electronic and elastic properties of mixed-metal diborides Re_0.5Ir_0.5B₂, Re_0.5Tc_0.5B₂, Os_0.5W_0.5B₂ and Os_0.5Ru_0.5B₂. The elastic moduli decrease from pure metal diboride ReB₂ to Re_0.5Ir_0.5B₂ and on the contrary increase from OsB₂ to Os_0.5W_0.5B₂ because boron–metal interactions are contaminated by the occupied anti-bonding orbitals. Alloying ReB₂ (OsB₂) with Tc (Ru) decreases the elastic moduli owing to the relativistic effects. Mixed-metal effects on elastic deformations focus on bonding strengths, which effectively tune the elastic properties of metal diborides.