Coherent phonon transport and Anderson localization in WS2/MoS2 superlattices

Understanding the interplay between coherent and incoherent phonon transport is essential for designing efficient nanoscale devices. Although many studies focus on three-dimensional materials, we still lack a systematic understanding of wave-based transport and localization effects in two-dimensional systems. Here we show that perfectly periodic heterostructures made of alternating layers of tungsten disulfide and molybdenum disulfide exhibit a non-monotonic pattern in their thermal conductance profile, a direct signature of coherent transport. In contrast, introducing aperiodicity leads to the emergence of Anderson localization, visible as an exponential decay of phonon transmission with superlattice length. Using first-principles combined with atomistic Green-function calculations, we quantify how structural disorder suppresses in-plane thermal conductance through coherent localization rather than incoherent scattering. These findings clarify how distinct coherent transport regimes arise in ordered versus aperiodic two-dimensional superlattices, and establish principles for controlling heat flow through wave interference in layered materials. Efficient heat management in nanoscale electronics depends on the precise control of vibrational waves known as phonons. This research reveals that while periodic layered materials allow these waves to travel coherently, structural disorder triggers Anderson localization, trapping the waves and significantly reducing heat flow.