Prediction of Stable Ruthenium Silicides from First-principles Calculations: Stoichiometries, Crystal Structures, and Physical Properties

Chuan-Zhao Zhang, Xiaoyu Kuang, Yuan-Yuan Jin, Cheng Lu, Dawei Zhou, Peifang Li, Gang Bao, Andreas Hermann

Research output: Contribution to journalArticlepeer-review

Abstract

We present results of an unbiased structure search for stable ruthenium silicide compounds with various stoichiometries, using a recently developed technique that combines particle swarm optimization algorithms with first-principles calculations. Two experimentally observed structures of ruthenium silicides, RuSi (space group P213) and Ru2Si3 (space group Pbcn), are successfully reproduced under ambient pressure conditions. In addition, a stable RuSi2 compound with β-FeSi2 structure type (space group Cmca) was found. The calculations of the formation enthalpy, elastic constants, and phonon dispersions demonstrate the Cmca-RuSi2 compound is energetically, mechanically, and dynamically stable. The analysis of electronic band structures and densities of state reveals that the Cmca-RuSi2 phase is a semiconductor with a direct band gap of 0.480 eV and is stabilized by strong covalent bonding between Ru and neighboring Si atoms. On the basis of the Mulliken overlap population analysis, the Vickers hardness of the Cmca structure RuSi2 is estimated to be 28.0 GPa, indicating its ultra-incompressible nature.
Original languageEnglish
Pages (from-to)26776-26782
Number of pages7
JournalACS Applied Materials & Interfaces
Volume7
Issue number48
DOIs
Publication statusPublished - 18 Nov 2015

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