Pd₂ZrIn Heusler Superconductor: Structural Disorder, Electronic Structure, Superconducting Ground State, and First-Principles Research Gaps - A Review
DOI:
https://doi.org/10.70882/josrar.2026.v3i2.285Keywords:
Heusler compounds, Pd₂ZrIn, Superconductivity, van Hove singularity, Muon spin relaxation, Density functional theory, Antisite disorderAbstract
The full-Heusler compound Pd2ZrIn (space group Fm3̄m, No. 225) belongs to a family of palladium-based Heusler superconductors alongside Pd2ZrAl, Pd2HfAl, and Pd2HfIn whose occurrence of superconductivity was originally predicted from electronic-structure calculations and subsequently confirmed by resistivity and magnetic-susceptibility measurements. This review synthesizes the currently available experimental and first-principles literature on Pd2ZrIn, covering its crystal structure and characteristic B2-type antisite disorder, the van Hove scenario invoked to rationalize its occurrence of superconductivity, and the detailed superconducting ground state recently established by muon spin relaxation and rotation (μSR) measurements namely bulk type-II superconductivity with Tc ≈ 2.2 K, a fully gapped, nodeless s-wave order parameter [Δ(0) ≈ 0.33 meV], and preserved time-reversal symmetry. Pd2ZrIn is placed in the broader context of the valence-electron-count (VEC) systematics that organize known Heusler superconductors, and is compared with isostructural and closely related compounds (Pd2ZrAl, Pd2HfAl, ZrPd2Sn, LiPd2Si, MgPd2Sb, ScAu2Al). Although the original 2009 work included electronic-structure calculations for the Pd₂ZrAl/Pd₂HfAl/Pd₂ZrIn/Pd₂HfIn family, the literature located for this review does not provide a dedicated, comprehensive Pd₂ZrIn-specific first-principles treatment of its equilibrium structural parameters, elastic/mechanical response, disorder-dependent electronic structure, phonon dispersion, Eliashberg spectral function α²F(ω), and ab initio electron–phonon coupling. These quantities therefore remain well-defined targets for a focused DFT/DFPT investigation. This review identifies these gaps and outlines a computational framework by which they could be addressed.
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