Coupled Interlayer–Intralayer Interactions for Promising Optoelectronic Response in ACeSiX4 (A = K, Rb, Cs; X = S, Se)

Abstract

Simultaneously achieving a wide band gap, strong optical absorption, and efficient carrier transport remains a fundamental challenge for layered chalcogenide semiconductors. Here, based on first-principles calculations and many-body perturbation theory, we propose a coupled interlayer–intralayer interaction strategy to regulate the electronic structure and carrier transport of layered ACeSiX4 (A = K, Rb, Cs; X = S, Se). By jointly tuning interlayer spacing and intralayer orbital hybridization, these wide-band gap compounds exhibit excellent structural, mechanical, and thermodynamic stability. Carrier transport calculations reveal pronounced anisotropy. RbCeSiSe4 exhibits a high carrier mobility (9.24 × 102 cm2 V–1 s–1) a strong absorption in the visible-light range. Thermodynamic analysis further demonstrates that the transformation from ACeSiS4 to ACeSiSe4 is energetically feasible; the calculations suggest favorable formation energetics. These results establish coupled interlayer–intralayer interaction as an effective design principle for high-quality and scalable Ce-based layered semiconductors and optoelectronic devices, providing a robust model framework for next-generation semiconductor materials.