Giant near-field radiative heat transfer between MXene sheets

Understanding the energy transfer mechanisms of near-field thermal radiation is crucial for applications such as near-field imaging, thermophotovoltaics, and thermal circuit devices, where precise thermal control at nanoscale distances is essential. Near-field energy transfer is primarily achieved through evanescent waves and photon tunneling effects, which dominate at sub-wavelength separations. Here, we present a comprehensive investigation of near-field radiative heat transfer (NFRHT) between MXene sheets, revealing their exceptional performance for nanoscale thermal management. Through systematic comparison with conventional materials, we reveal that MXene exhibits a giant heat transfer enhancement - achieving a remarkable coefficient of 10⁵ W/(m² ·K) at 10 nm gaps-equivalent to a 10⁴-fold improvement over the blackbody limit. We identify the dominant mechanism as strong coupling of transverse magnetic (TM) polarized surface plasmon polaritons (SPPs), contrasting with frustrated total internal reflection observed in thicker materials. Comparative analysis further shows MXene outperforms monolayer silver films and even designated graphene in the sub-50 nm gap regime, owing to its unique tunable dielectric properties and high carrier concentration, along with its mechanically superior structural properties compared to conventional metals. Moreover, we establish that monolayer MXene delivers optimal performance, with heat flux reaching 2100 times the blackbody limit at 10 nm gaps. Finally, the effects of temperature variation, doping concentration, separation distance, and substrate interactions are quantitatively characterized, offering complete guidelines for practical implementation. These findings thus not only advance fundamental understanding of NFRHT in 2D materials but also establish MXene as a promising platform for next-generation thermal management systems and thermophotovoltaic applications.