Lorentzian function-based simulation and analysis of spectral behaviour in phase-change memory

Phase Change Memory (PCM) materials, including Ge₄Sb₆Te₇ (GST467), are increasingly recognized in advanced data storage for their rapid switching capabilities and scalability. This work presents a MATLAB-based simulation study employing the Lorentzian function to investigate the effect of variations in the half-width at half-maximum (Γ) on the spectral profile, and how these variations can be correlated with the material states of GST467. The study begins with single-peak Lorentzian simulations to isolate the role of Γ, showing that increasing Γ broadens peaks and reduces intensity while conserving the overall area. This provides a theoretical basis for interpreting broadening as a signature of structural disorder. The approach is then extended to synthetic multi-peak spectra, demonstrating how overlapping Lorentzian components approximate the complexity of GST Raman features. The comparisons with existing experimental Raman spectra signify that narrow Γ values are related to crystalline states, while broader Γ values are associated with amorphous or mixed states. Statistical fitting (R², reduced χ²) benchmarks Lorentzian models against Gaussian and Voigt alternatives. The novelty of the study lies in the quantitative linking of Γ variations to the degree of crystallinity and disorder in PCM materials. This method facilitates a comprehensive analysis of spectral fluctuations during phase transitions by simulating a broad spectrum of Γ values and connecting them with experimental results. The results demonstrate that even slight modifications in Γ serve as sensitive markers of material condition, exceeding traditional peak position or intensity assessments. This study enhances Raman spectroscopy by including a MATLAB simulation-assisted method for monitoring phase transitions in phase change materials (PCM). This methodology can be utilized for various chalcogenide memories, facilitating the advancement of swifter and more efficient phase change memory technologies.