Giant thermal rectification beyond structural asymmetry via current-induced nonreciprocity effects

Pursuing significant thermal rectification effect with minimal temperature differences is critical for thermal rectifiers. While asymmetric structures enable spectral matching, they inherently limit thermal rectification performance. To address this issue, we developed a thermal rectification structure comprising a current-biased graphene-coated silicon carbide (SiC) substrate paired with another graphene-coated SiC substrate separated by a nanoscale vacuum gap. A current-biased graphene sheet generates nonreciprocal effect that actively modulates radiative energy transfer. Our theoretical framework demonstrates that the current-biased graphene achieves a high thermal diode efficiency even under a modest temperature difference. Remarkably, the thermal diode efficiency exceeds 0.8 at a temperature difference of just 100 K (between 300 K and 400 K). These findings highlight the synergistic enhancement from graphene coatings and current biasing, providing a viable strategy for nanoscale thermal management applications.