Feasibility of crystalline isostructural X2Sb2Te5 (X = Ge, Si) phase change materials in memory storage devices: First principles calculations

•Electronic and optical properties of Ge2Sb2Te5 and Si2Sb2Te5 using first ever FP-LAPW-mBJ method.•Use of mBJ potential is validated for accurate electronic and optical response.•Optical properties depict feasibility of using both compounds in optical memory storage devices.

We have investigated the electronic and optical response of two isovalent non-volatile memory compounds, Ge2Sb2Te5 and Si2Sb2Te5, by employing the full potential linearized augmented plane wave method. Self consistent first-principles calculations were performed for the first time by using modified exchange potential of Becke and Johnson namely mBJ potential. Topology of energy bands and density of states of both the compounds are discussed. The optical properties such as dielectric constants, refractive indices, reflection spectra, extinction coefficients are also discussed in order to throw more light on the applicability of these compounds in memory storage devices.

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