First principles study of the structural, elastic, electronic and optical properties of CaSrTt (Tt=Si, Ge, Sn and Pb)

► Structural, elastic, electronic and optical properties of CaSrTt (Tt=Si, Ge, Sn and Pb). ► The electronic structure reveals a strong interaction between the Tt and Ca atoms. ► The bonding of CaSrTt has a combination of covalent and ionic nature. ► The energy band gap calculations suggest that CaSrTt are semiconductors. ► The optical parameters are calculated between 0 and 45 eV.