Anisotropic control of the entanglement-criticality crossover in a Gamma-modified XY chain.

We investigate the structure of quantum and classical correlations in the generalized off-diagonal Gamma spin chain, focusing on the interplay between interaction range and anisotropy across an interaction-driven quantum phase transition. By combining concurrence, quantum discord, Fermionic Correlation Participation (FCP), entanglement entropy, and central-charge scaling, we develop a unified multiscale characterization that connects two-site correlations, collective fermionic organization, and universal critical behavior. A central finding is the existence of a finite separation between the entanglement-vanishing point and the quantum critical point throughout the XY regime (0 < δ < 1), which collapses continuously as the system approaches the Ising limit. These results demonstrate that bipartite entanglement suppression and criticality are not generically equivalent in anisotropic long-range systems. Anisotropy progressively aligns the entanglement structure with the quantum critical point; however, in weakly anisotropic regimes the system remains in a critical phase with divergent correlations even after pairwise entanglement has vanished. Quantum discord, FCP, and entanglement entropy scaling collectively show that this suppression reflects a redistribution and geometric reorganization of correlations rather than their absence. Our results clarify the nontrivial relationship between entanglement, correlation geometry, and criticality in extended quantum systems, and have direct implications for engineered quantum spin systems with tunable anisotropic exchange couplings.