Far-field radiation of biased monolayer PbBiI

Abstract

We use the Kubo formula and linear response theory to study the radiation of energy and angular momentum from biased monolayer PbBiI. Our results show that a critical bias field Vbc≃0.326 eV emerges for the radiations. For bias fields below Vbc, there is a negligible shift of the threshold frequency at which the spin-dependent energy radiation is maximum, while above which, it significantly moves to the higher frequencies. At all the threshold frequencies, the sign of possible angular momentum radiations is switched. Further, we find that contrary to Planck's law which is valid for the unbiased energy radiation (proportionality to T4), the biased one is proportional to T5. Also, it is possible to confirm the behaviors of the system below and above Vbc via the temperature-dependent angular momentum radiation. This work illuminates/engineers the application of angular momentum degree of freedom in processing data.