Structural, electronic, elastic and optical properties of full Heusler compounds Li₂CaC and Li₂SrC were studied; using the full potential linearized augmented plane wave method based on the density functional theory, implemented in the Wien2k package. The exchange and correlation potential is treated by the generalized gradient approximation GGA and Trans-Blaha-modified Becke–Johnson. We have found that the structure of Cu₂MnAl-type has more stable energy than the one of Hg₂CuTi-type for both compounds studied. These compounds have semiconductor behaviour with a direct band gap at Γ-Γ direction with values of 1.127 eV and 0.979 eV for Li₂CaC and Li₂SrC respectively. The calculated formation and cohesive energies are all negative, which exhibit that these alloys have a good chemical stability. The optical properties shows a high absorption coefficient,which gradually increases from 7 × 10⁴cm⁻¹ to 39 × 10⁴cm⁻¹ through the visible domain of light, and the high reflectivity which exceeds 30% in the visible domain of light for both compounds, allowing the useful of these full Heusler materials in optoelectronic applications, including solar and photovoltaic cells. Although, no available theoretical or experimental results for these compounds to compare it with our findings. We hope that this study can pave the way for experimental or theoretical research in the future.

研究了完整的Heusler化合物Li ₂ CaC和Li ₂ SrC的结构，电子，弹性和光学性质。使用基于Wien2k软件包的基于密度泛函理论的全势线性化增强平面波方法。交换和相关势由广义梯度近似GGA和Trans-Blaha修正的Becke-Johnson处理。我们发现对于所研究的两种化合物，Cu ₂ MnAl型结构比Hg ₂ CuTi型结构具有更稳定的能量。这些化合物具有半导体行为，在Γ-Γ方向上具有直接带隙，对于Li ₂ CaC和Li ₂，其值为1.127 eV和0.979 eV。SrC分别。计算得出的形成能和内聚能均为负，表明这些合金具有良好的化学稳定性。光学性质显示出高吸收系数，该吸收系数在可见光范围内从7×10 ⁴ cm ^-1逐渐增加到39×10 ⁴ cm ^-1，并且高反射率在可见光范围内超过30％。两种化合物，使这些完整的Heusler材料在光电应用中有用，包括太阳能电池和光伏电池。尽管这些化合物尚无可用的理论或实验结果与我们的发现进行比较。我们希望这项研究可以为将来的实验或理论研究铺平道路。