Source capture
Authors Yu-Cheng Zhu, Jia-Xi Zeng, Xin-Zheng Li
arXiv / Publisher https://arxiv.org/abs/2602.03576
PDF https://arxiv.org/pdf/2602.03576
Relevance score 4.945
Primary category cond-mat.supr-con
Published 2026-07-30
Research paradigm Theoretical
Sample form Unknown

Summary

This study employs first-principles path-integral molecular dynamics to comprehensively incorporate nuclear quantum many-body effects, constructing free energy surfaces and revealing a lattice quantum disordered (LQD) phase in H3S and La3Ni2O7. By comparing classical and quantum phase boundaries, the LQD phase forms a triangular region in the pressure–temperature phase diagram, with its left boundary precisely aligning with the transition temperature of the left flank of the superconducting dome; notably, the maximum temperature Tcmax of the LQD phase coincides with the maximum superconducting Tc, and the isotope effect is accurately captured. These findings demonstrate that superconductivity on the dome’s left flank originates from a transition from a low-symmetry phase to the quantum disordered phase, with the superconducting state residing entirely within the high-symmetry phase, thereby refuting the two-phase interpretation. The research establishes the LQD phase as a unified framework that not only elucidates the critical role of lattice quantum many-body effects in unconventional superconductivity but also opens new pathways for predicting higher-Tc superconductors and explaining anomalous condensed-matter phenomena.

Materials

Methods

  • path-integral molecular dynamics (PIMD)
  • DFT
  • machine learning inter-atomic potentials
  • centroid potential of mean force
  • conventional molecular dynamics (MD)

Keywords

Highlights

  • First rigorous description of a lattice quantum disordered phase in real materials using first-principles path-integral molecular dynamics.
  • The precise alignment between the left LQD boundary and the superconducting dome's left flank reveals the origin of superconductivity on the left flank.
  • The maximum temperature of the LQD phase exactly matches the maximum superconducting Tc for both H3S and La3Ni2O7.
  • The LQD phase transcends the conventional phonon picture and may host a novel pairing mechanism.
  • This framework provides a practical route for predicting higher-Tc superconductors by identifying materials with a large LQD phase.

Conclusions

  • A lattice quantum disordered (LQD) phase is discovered in H3S and La3Ni2O7 via first-principles PIMD.
  • The left boundary of the LQD phase precisely aligns with the left flank of the superconducting dome.
  • The maximum temperature of the LQD phase coincides with the maximum superconducting transition temperature Tc.
  • Superconductivity on the left flank originates from a transition from a low-symmetry phase to the LQD phase and resides entirely in the high-symmetry phase, refuting two-phase interpretations.
  • The LQD phase is a key ingredient of the pairing mechanism and establishes lattice quantum disorder as a unifying framework for unconventional superconductivity.

Main claims

  • The left flank of the superconducting dome in H3S and La3Ni2O7 originates from the structural transition into the lattice quantum disordered phase.
    • Evidence: Left boundary of LQD phase coincides with Tc values on the dome’s left flank.,Isotope effect in superconductivity accurately captured by LQD phase boundaries.
  • The maximum temperature of the LQD phase coincides with the maximum superconducting Tc, establishing the LQD phase as a decisive factor in the pairing mechanism.
    • Evidence: T_max(LQD) = 220 K (H3S), 160 K (D3S), 77 K (La3Ni2O7) match experimental peak Tc.,Agreement robust across different exchange-correlation functionals.

Workflow

  • sample_preparation — Computational models of superconducting materials established for quantum and classical simulations.
    • Materials: H3S; La3Ni2O7
    • Methods: first-principles DFT calculations with PBE functional; machine learning inter-atomic potentials generation
    • Observations: potential energy surfaces using the computational models prepared for PIMD and MD simulations
  • measurement — Nuclear quantum many-body effects and thermal fluctuations included; structural phase boundaries identified via spectral and structural data.
    • Materials: H3S; La3Ni2O7
    • Methods: path-integral molecular dynamics (PIMD); classical molecular dynamics (MD)
    • Observations: lattice dispersion from centroid effective forces; soft-mode frequency at Γ point across P and T; pair distribution function from MD
  • analysis — Lattice quantum disordered phase defined; its left boundary aligns with experimental Tc on the left flank of the superconducting dome.
    • Methods: centroid potential of mean force from PIMD to construct free energy surface; curvature analysis to locate phase boundaries; comparison of quantum (PIMD) and classical (MD) boundaries
    • Observations: quantum phase boundary shifting to higher pressure with T; classical phase boundary; triangular LQD region; T_max(LQD) values: 220 K for H3S, 160 K for D3S, 77 K for La3Ni2O7
  • interpretation — Superconductivity on the dome’s left flank originates from the transition into the LQD phase; the superconducting state resides entirely within the high-symmetry phase; LQD phase is a key pairing mechanism ingredient.
    • Materials: H3S; La3Ni2O7
    • Methods: direct comparison with published experimental Tc data; isotope effect validation (H3S vs D3S)
    • Observations: left LQD boundary precisely tracks the left flank Tc; T_max(LQD) matches peak Tc (220 K, 80 K); isotope effect captured