Insight View of Topological Nontrivial Nature in the Novel Alkali Metal–Based Quaternary Heusler Compounds via Ab Initio Calculations

In this paper, we have highlighted a first-principles study of the structural stability and electronic behavior of the novel alkali metal–based quaternary Heusler compounds (LiNaCuAs, LiKCuAs, NaKCuAs, LiRbCuAs, NaRbCuAs, and KRbCuAs), using the full-potential linear muffin-tin orbital (FP-LMTO) method. The obtained results show that our compounds are energetically more stable in the Hg2CuTi-type structure. The calculated electronic properties with and without spin-orbit coupling (SOC) effects indicate that the majority of compounds naturally present a band inversion order which confirmed the topological nontrivial behavior of these materials. In addition, our results show that SOC is not a primary cause of the band inversion mechanism. The obtained values of the calculated formation energy confirm the physical stability of these compounds against decomposition, and they can be passed in fabrication level.