Tunable near-field radiative heat transfer with the shear polariton in three-body low-symmetry crystals

The singularity optical phenomena induced by broken symmetry within crystals have recently received widespread attention. In particular, the shear polaritons supported by low-symmetry crystal can improve the controllability of light propagation direction, making them have great potential for application in thermophotonics research. In this paper, we theoretically studied the near-field thermal radiation (NFTR) behavior of a three-body monoclinic crystal system. It is found that three-body systems can enhance NFTR over a wide frequency range by several orders of magnitude beyond the blackbody radiation limit, and the relative rotation of the middle body can play a role manipulation the NFTR between two low-symmetry crystal semi-infinite plates, in particular, the appearance of shear effect in low-symmetry crystals enhances the in-plane anisotropy of the twist-induced NFTR, providing extra approach for harnessing the NFTR of the system. We believe that the enhancement and control scheme of NFTR in the three-body systems can find potential applications in the fields of the realm of nanoscale thermal management.