Abstract We report the structural, elastic, electronic, optical and vibrational properties of double half Heusler (DHH) compounds Ti2FeNiSb2 and Ti2Ni2InSb within density functional theory (DFT) for the first time. The calculated elastic constants express that both compounds are mechanically stable and show ductile mechanical character. Computed band structures of these compounds indicate typical semiconductor behaviour with the band gap energies of 0.63 eV for Ti2FeNiSb2 and 0.42 eV for Ti2Ni2InSb. We have also searched the optical properties such as the dielectric function, optical conductivity, refractive index, absorption index and reflectance for both compounds. Besides, we have computed vibrational properties i.e. zone-centre Raman and infrared phonon modes along with the phonon dispersion relations and phonon density of states of surveyed compounds.

中文翻译：

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Ti2FeNiSb2 和 Ti2Ni2InSb 双半赫斯勒合金的电子结构、光学和振动性能

摘要 我们首次在密度泛函理论 (DFT) 中报道了双半赫斯勒 (DHH) 化合物 Ti2FeNiSb2 和 Ti2Ni2InSb 的结构、弹性、电子、光学和振动特性。计算出的弹性常数表明这两种化合物都是机械稳定的，并显示出可延展的机械特性。这些化合物的计算能带结构表明典型的半导体行为，Ti2FeNiSb2 的带隙能量为 0.63 eV，Ti2Ni2InSb 的带隙能量为 0.42 eV。我们还研究了两种化合物的光学特性，例如介电函数、光导率、折射率、吸收指数和反射率。此外，我们计算了振动特性，即