A crystal consists of a honeycomb lattice. It is invariant under a rotation of angle θ = π/6 in the horizontal plane around the vertical axis. This means that thephysical properties of the crystal are the same after such a rotation. Show that the symmetric thermal conductivity tensor κ is written in components as,where κ_|| is the thermal conductivity along the vertical rotation axis and κ_⊥ is the thermal conductivity in the horizontal plane of rotation.

Transcribed Image Text:

К = KI 0 0 0 0 KI 0 lly 0