2026/07/22 by Li Wang, Yunjie Ye
#cond-mat.mtrl-sci #cond-mat.mes-hall #quant-ph
Incommensurability and elastic reconstruction do not by themselves define a structurally superlubric phase. We define fully sliding and pinned zero-temperature phases by \limsupA→∞τ\rm depmax(A)=0 and \liminfA→∞τ\rm depmin(A)>0, respectively; Λn=|Vn|Gn,i[D\rm rel-1(\mathbf qn)]ijGn,j measures only reconstruction susceptibility. Translational covariance then proves that a clean, smooth, infinite moiré continuum can reconstruct without acquiring a bulk sliding barrier. We restore atomic sampling in a two-dimensional discrete model of graphene/hBN and test both a diffusion quantum Monte Carlo first-star potential and a 15-harmonic Leven potential across three rational approximants and five directions. No physical-coupling equilibrium or metastable barrier is resolved. The Leven spectrum raises the largest tested Λ from 0.142 to 0.212, while artificial scaling through Λ=1 reaches uncontrolled strain before a size-independent threshold appears. The tested zero-temperature in-plane models are therefore consistent with an elastically relaxed sliding regime; Λ=1 is a reconstruction scale, not a static phase criterion.