Far-field thermal properties of β borophene under an external electric field.

Borophene has been reported as the latest very promising 2D material. We theoretically investigate the thermal radiation of β borophene. β borophene has been composited on Ag substrate. Theoretical research frequently mentions three types of model of β borophene. The energy bands of the three models are different. Homogeneous and inversion symmetric models have a gapless Dirac cone near the (') point, while they are gapped in the inversion non-symmetric model. The homogeneous model has gapless triplet fermions and three-band touching points at high-symmetry points. The optical conductivity exhibits peaks due to the energy transition of high-symmetry points. The radiation spectrum follows Wien's displacement law in homogeneous and inversion symmetric models, while it is broken in the inversion non-symmetric model. The total energy radiation changes as the voltage increases for the three β borophene models. The radiation of energy can be controlled by applying a suitable voltage.