Reinterpreting the LK-99 Puzzle Through a Sandwich Heterostructure Framework for Ambient Superconductivity

Abstract

The 2023 LK-99 incident—in which copper-doped lead apatite was claimed to exhibit room-temperature ambient-pressure superconductivity—triggered a global frenzy of replication attempts, nearly all of which ended in failure. Two findings from these efforts were widely interpreted as the final refutation of LK-99’s superconductivity: (1) pure-phase single crystals synthesized by the Max Planck Institute are highly insulating; and (2) the sharp resistivity drop observed near 400 K originates from the first-order structural phase transition of Cu₂S impurities. Here, reinterpreting these findings through the Spacetime Ladder Theory (STLT) — an effective field theory that describes superconductivity as a topological phase transition from open strings (electrons bound to the lattice) to closed strings (Cooper-pair-like vortex loops) — we demonstrate that these “failures” are not refutations at all. Instead, they precisely constitute the two essential building blocks of a room-temperature superconducting “sandwich” heterostructure: a high-impedance insulating shell (pure-phase lead apatite, suppressing Qi-field leakage, ) and a coherent active core (Cu–O–Cu or Au–O–Au ordered chains embedded within the apatite channels, achieving perfect phase matching, ). The central thesis of this work is that room-temperature superconductivity is a property of architecture rather than of a homogeneous material. We present numerical simulations within the STLT framework for four scenarios: pure insulator ( K); disordered Cu-doped polycrystal ( K); the accidentally realized ordered-chain sandwich that likely underlay the original LK-99 levitation ( K); and an Au-optimized design predicted to reach – K. We provide four falsifiable experimental predictions and a complete fabrication protocol. The LK-99 puzzle thus offers not a debunked claim but an unexpected blueprint: deliberately engineered heterostructures, not homogeneous crystals, may be the path to reproducible ambient superconductivity.

Abstract of "Reinterpreting the LK-99 Puzzle Through a Sandwich Heterostructure Framework for Ambient Superconductivity" by Binggong Chang, https://doi.org/10.5281/zenodo.20779429, used under its Creative Commons Attribution license (CC-BY); markup removed, otherwise unmodified.