Mechanism: Moiré-Enhanced Soft-Phonon Superconductivity (MESPS)

We exploit the moiré lattice of two superimposed atomic sheets with a controlled twist angle to engineer the phonon landscape. Instead of searching for a magic material, we take a mundane system (two layers of a simple metal or a dichalcogenide) and, by varying the angle, create ultra-soft phonon modes with effective energy of a few meV but with an electron-phonon coupling constant λλ enormously enhanced, up to values of 3–5.The coupling is so strong that the Allen-Dynes formula modified for soft-mode (where the average phonon frequency ⟨ω⟩ drops while λ rises) can yield Tc at room temperature even though the frequencies are low, because the product ⟨ω⟩exp(−1/λ) can become large if λ is sufficiently high.This is a radical revisiting of the idea of Ginzburg and Little (excitons, soft-mode) but with an ingredient completely absent in previous theories: the moiré lattice as an artificial generator of soft phonons coupled to flat electronic bands. This combination has never been formalized into a room-temperature superconductivity proposal before