Compositional tuning of metastable ferroelectric phases and Landau-reconstructed negative-capacitance energy landscapes in combinatorial Hf1-xZrxO2 thin films

Hafnium-zirconium oxide-based ferroelectrics are emerging as key materials for low-power nanoelectronic devices, yet stabilizing their metastable ferroelectric phases remains a fundamental challenge. Here, we report a combinatorial experimental – theoretical study on Hf 1-x Zr x O 2 thin films (0.1 ≤ x ≤ 0.9), synthesized by reactive co-sputtering on a single-wafer platform to systematically map phase evolution and energy landscapes. X-ray diffraction reveals the coexistence of tetragonal, orthorhombic and monoclinic phases across the compositional gradient, with Hf 0.5 Zr 0.5 O 2 showing the highest orthorhombic phase stability. Ferroelectric measurements demonstrate robust polarization switching and enhanced remnant polarization near the equiatomic composition. Landau free-energy reconstruction based on experimentally measured ferroelectric characteristics reveals composition-dependent negative-capacitance energy landscapes, providing indirect evidence of potential negative-capacitance behaviour in Hf 1-x Zr x O 2 thin films. Landau-based free energy analysis and TCAD simulations reveal pronounced double-well energy profiles and stabilized negative capacitance behaviour for Hf 0.5 Zr 0.5 O 2 compositions. Density functional theory calculations further reveal balanced electronic hybridization, asymmetric effective potential modulation and anisotropic charge distribution, confirming the favorable stabilization of a metastable phase at x ≈ 0.5. This work presents a comprehensive correlation between composition, structure and energy, providing a scalable pathway to engineer metastable ferroelectric states for next-generation negative capacitance transistors and energy-efficient non-volatile memory technologies.