Strong anisotropic thermal conductivity of monolayer WTe2

Tungsten ditelluride (WTe2) has attracted increasing attention due to its large magnetoresistance and pressure-induced superconductivity. In this work, we investigate the thermal conductivity (kappa) of monolayer WTe2 by performing first-principles calculations, and find strong anisotropic kappa with predicted room-temperature values of 9 and 20 W m(-1) K-1 along two principal lattice directions, respectively. Such strong anisotropy suggests the importance of orientation when engineering thermal-related applications based on WTe2. The anisotropy of. is attributed to the in-plane linear acoustic phonon branches, while the out-of-plane quadratic acoustic phonon branch is almost isotropic. The size dependence of kappa shows that the size effect can persists up to 10 mu m, and the anisotropy decreases with decreasing sample size due to the suppression of low-frequency anisotropic phonons by boundary scattering.