Signature of the topological surface state in the thermoelectric properties of Bi₂Te₃

We present ab initio electronic structure calculations based on density functional theory for the thermoelectric properties of Bi$_2$Te$_3$ films. Conductivity and thermopower are computed in the diffusive limit of transport based on the Boltzmann equation. Bulk and surface contribution to the transport coefficients are separated by a special projection technique. As a result we show clear signatures of the topological surface state in the thermoelectric properties.