Anisotropic Energy and Superconducting Properties in Van der Waals Layered Tin Pnictides: A Unified Model

This study establishes a mathematical relationship between the combined anisotropic energy (E*_combined) and key superconducting properties (T_c, λ, H_c, ξ) in van der Waals (vdW) layered tin pnictides, focusing on Na₁₋ₓSn_2P_2. By integrating crystallographic anisotropy with empirical scaling, we derive a unified model that explains the enhancement of T_c due to structural anisotropy and electronic tuning. The model predicts T_c ∝ (γ·E*_combined)/Θ_D^2, validated by experimental data (T_c = 2.0 K, γ = 5.31 mJ/mol·K^2, Θ_D = 237 K). This work provides a design principle for optimizing superconductivity in quasi-2D materials.