Thermal transport and disordered hyperuniformity in monolayer amorphous carbon

Two-dimensional (2D) crystals proved revolutionary soon after graphene was discovered in 2004. However, 2D amorphous materials down to a monolayer of atoms only became accessible in 2020 and remain largely unexplored. Here, we systematically explore the thermal transport in monolayer amorphous carbon (MAC). An ultralow cross-plane thermal conductivity (κ) is calculated for van der Waals stacked multilayers. Meanwhile, an unexpectedly high in-plane κ is obtained for freestanding monolayers which is a few times higher than 3D amorphous carbon with similar sp² fraction. These findings reveal the predominant role of reduced dimensionality. Furthermore, we introduce the concept of disordered hyperuniformity (DHU), a hidden long-range order, into the study of thermal transport in 2D amorphous materials. A notable correlation between the thermal transport behavior and the degree of hyperuniformity is observed, and the long-range correlation captured by DHU could enhance transport. These findings highlight the unique thermal properties of 2D amorphous materials, and open new avenues for understanding and manipulating thermal transport at the 2D limit.