Thermopower and thermoconductance properties of zigzag edged graphene nanoribbon based thermoelectric module

•The thermoelectric properties of zigzag edged graphene three terminal junction based thermoelectric module is investigated theoretically.•The thermopower shows a series of peaks and dips and the thermoconductance shows quantized values.•The quantized thermoconductance plateau is much clearer when the model is under the Hall regime.•The thermoelectric coefficients are very sensitive to disorder under some conditions.

The thermopower S and thermoconductance κ   properties of graphene nanoribbon based three terminal thermoelectric module are studied theoretically in two cases: with magnetic field and without magnetic field. By using the non-equilibrium Greenʼs function method combined with the Landauer–Büttiker formula, the electric current and linear electrical conductance through the system is obtained. The S–EFS–EF curves show a series of peaks and dips and κ–EFκ–EF curves show plateau structures. The κ–EFκ–EF relation is roughly linear when there is no magnetic field and is parabolic when in the quantum Hall regime because of the unique Dirac fermion in graphene. The dependence of S and κ on the on-site energy of the terminals, sample size and Anderson disorder are investigated as well.