Anisotropy-Governed Superconducting Properties in CoZr₃: A Multiscale Theoretical and Experimental Study

Abstract

his work establishes a comprehensive multiscale framework connecting atomic-scale anisotropy to macroscopic superconducting behavior in orthorhombic CoZr₃. Through synergistic density functional theory (DFT) calculations and advanced synchrotron characterization, we reveal:

1. Microscopic Origins: Quantified the anisotropy energy (E₁* = 0.69 ± 0.05) through a crystallographically-validated Hamiltonian incorporating Zr 4d-Co 3d orbital hybridization effects.

2. Thermal-Mechanical Coupling: Demonstrated uniaxial negative thermal expansion (α_c = -8.2 ± 0.3 μK⁻¹) persists across 90-800 K, originating from low-energy phonon modes along the c-axis while maintaining superconductivity (T_c = 4.3 K).

3. Property Relationships: Derived compositionally-tunable scaling laws:

   • B_c2 ∝ (E₁*/ρ_n)^0.5 (ρ_n = normal-state resistivity)

   • J_c = J_c0 exp[-U_0(1 + 0.1E₁*)/k_BT]

These insights enable predictive design of quantum materials with coupled thermal-electronic functionality.