Disorder-Free Solitonlike Energy Transport in Moiré-Engineered Phononic Flat Bands.

The pursuit of low-loss, directional energy transport and heat localization is critical in frontier fields such as hybrid quantum computing, thermophysics, and materials science. Localized phonon modes, with spatially confined vibrational energy and suppressed diffusive scattering, provide promising routes toward this goal. However, conventional approaches to phonon localization necessitate material disorder or nonlinear interactions, limiting their potential for controllable, on-demand energy routing and concentration in pristine, scalable materials. In this Letter, we demonstrate disorder-free, solitonlike phonon transport in atomic moiré superlattices (AMS), arising purely from engineered moiré interlayer interactions and characterized by non-Anderson localization and phononic flat bands. The vibrational energy is robustly confined at AA-stacking regions of 1D-AMS, and evolves into solitonlike propagation along moiré-induced channels in translational 2D-AMS. Furthermore, we show that coaxial double-wall moiré nanotubes leverage anisotropic interwall coupling to achieve simultaneous azimuthal localization and axial channelized transport, enabling programmable, low-dispersion phononic signal transmission with minimal crosstalk. By bridging concepts from classical wave physics and quantum moiré materials science, this Letter reveals a method for controlling phononic energy routing and local entropy landscapes in designed atomic structures. This moiré phononics approach holds great potential in thermal logic circuits, low-loss phonon-based communication networks, and phononic information processing in van der Waals structures.