  Anisotropic phonon transport along different lattice directions of
two-dimensional (2D) materials has been observed, however, the effect decreases
with increasing the thickness beyond a few atomic layers. Here we establish a
novel mechanism to induce anisotropic phonon transport in quasi-2D materials
with isotropic symmetry. The phonon propagation is guided by resonance
hybridization with surface nanostructures. We demonstrate that the thermal
conductivity of 3 nm-thick silicon membrane with surface nanofins is greater by
$\sim50\%$ parallel to the fins than that perpendicular to the fins.
