New Stable Phases in the Re-B System: A First-principles Study

ORAL

Abstract

We studied rhenium borides using genetic algorithm in combination with first-principles calculations and revealed several new stable phases in the Re-B system. The structures obtained from our genetic algorithm search are energetically much superior to those proposed in the literature. Two new phases of Re2B were found to be thermodynamically stable at different pressures, which possibly explains the recent experimental observations (Solid State Sciences 25 85-92 (2013)). ReB is stable against decomposition reactions below 10 GPa and ReB3 is stable above 22 GPa. A C2/m structure was discovered for ReB4 to have lower energy than the R-3m structure reported earlier (J. Alloys Compd. 573 20-26 (2013)). Elastic properties from first-principles calculations indicate that the structures we report in this work are mechanically stable and promising targets as new ultra-hard materials.

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Authors

  • Xin Zhao

    Iowa State University

  • Manh Cuong Nguyen

    Ames Lab, Iowa State University

  • Cai-Zhuang Wang

    Ames Lab, Ames Laboratory-U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011, USA, Ames Laboratory, DOE \& Iowa State University, Iowa State University, Ames laboratory--US DOE and Iowa State University, Ames Laboratory, Ames Laboratory - U.S. Department of Energy, Iowa State University, Ames Lab, US DOE

  • Kai-Ming Ho

    Ames Lab, Ames Laboratory-U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011, USA, Ames Laboratory, DOE \& Iowa State University, Iowa State University, Ames Laboratory, Ames Laboratory - U.S. Department of Energy, Iowa State University