Spin-dependent thermoelectric transport properties of Cr-doped blue phosphorene

We systematically investigate the thermoelectric (TE) properties of the Cr-doped blue phosphorene (blue-P) along the armchair and zigzag directions. First, we find the semiconducting band structure of the blue-P will become spin-polarized due to the Cr-doping, and can be seriously changed by the doping concentration. Then we show the Seebeck coefficient, the electronic conductance, the thermal conductance, and the figures of merit ZTs are all dependent on the transport directions and doping concentration. However, two pairs of the peaks of the charge and spin ZTs can be always observed with the low-height (high-height) pair on the side of the negative (positive) Fermi energy. In addition, at temperature 300 K the extrema of the charge (spin) ZTs of the blue-P along the two directions are kept to be larger than 22 (90) for the different doping concentrations and will be further enhanced at lower temperature. Therefore, we believe the Cr-doped blue-P should be a versatile high-performance TE material which may be used in the fields of the thermorelectrics and spin caloritronics.