Tin-tellurium-phosphide: Investigation of composition dependent band structure and its experimental realization

The experimental discernment of TCIs (topological crystalline insulators) and other Dirac materials in recent times, has opened a new platform for their applications in spin-electronics and quantum computing. A very promising material in thermoelectric and photovoltaic applications, namely SnTe, has been increasingly investigated by band engineering, however, there is not sufficient verification of any band-crossing characteristics or evolution of Weyl nodes yet. In this present study, we investigate a novel class of possible substitutional solid solutions of Sn, Te, and P of varying compositions by density functional theory, where specific crystal symmetry elements may allow the existence of robust topological states. With fine tuning of chemical composition, one can also locate the existence of Dirac-like nodes at certain points of the Brillouin zone from preliminary first-principle calculations. Apart from simulations, synthesis and structural examinations of Sn-Te-P, were also conducted. The structural analysis of a representative member of this system was also carried out with the help of the simulated XRD patterns, to indicate the existence of a new phase during synthesis in a condensed system combustion.