Gaussian-based computational Raman spectral reconstruction of GST467: Sb2Te3 core–shell phase change material with experimental validation and metal–insulator transition interpretation

Abstract

Phase change materials of the Ge–Sb–Te (GST) system are extensively utilized in non-volatile memory and neuromorphic computing devices owing to their high switching speed, scalability, and phase transition stability. Raman spectroscopy is a significant technique in understanding vibrational modes, bonding structures, and metal–insulator phase transitions in GST materials, and most of them are based on experimental observations without any computational Raman reconstruction, especially in core–shell phase change memory (PCM) materials. A Gaussian-based computational Raman spectral reconstruction framework is proposed for Ge₄Sb₆Te₇ (GST467) Sb₂Te₃ core–shell phase change materials using MATLAB simulation and experimental validation from the literature. The Raman spectra of GST467 and Sb₂Te₃ materials are simulated using Gaussian peak fitting and combined to produce a composite spectrum for the core–shell material. A comparative analysis of Ge₂Sb₂Te₅ (GST225) and GST467 materials is carried out to assess the width of the peaks, stability of the structure, and transition behaviour; the results are validated using the Root Mean Square Error (RMSE) and peak deviation methods. The metal–insulator transition behavior of the materials has been analyzed by using the Raman peak broadening method, which shows that the transition in conductivity for the GST467 material is smooth. The novelty of this work is that it proposes a structured framework for computational Raman reconstruction of GST467, namely Sb₂Te₃ core–shell PCM materials, with experimental validation and metal–insulator transition analysis.