The intrinsically low lattice thermal conductivity of monolayer T-Au6X2 (X = S, Se and Te)

The lattice thermal conductivities of T-Au 6 S 2 , T-Au 6 Se 2 and T-Au 6 Te 2 along the x -axis ( y -axis) are 0.25 (0.23), 0.30 (0.21) and 0.12 (0.10) W m −1 K −1 at 300 K, respectively. These values are much lower than those of many materials.