The engineering of cooling mechanisms is a bottleneck in nanoelectronics. Thermal exchanges in diffusive graphene are mostly driven by defect-assisted acoustic phonon scattering, but the case of high-mobility graphene on hexagonal boron nitride (hBN) is radically different, with a prominent contribution of remote phonons from the substrate. Bilayer graphene on a hBN transistor with a local gate is driven in a regime where almost perfect current saturation is achieved by compensation of the decrease in the carrier density and Zener–Klein tunnelling (ZKT) at high bias. Using noise thermometry, we show that the ZKT triggers a new cooling pathway due to the emission of hyperbolic phonon polaritons in hBN by out-of-equilibrium electron–hole pairs beyond the super-Planckian regime. The combination of ZKT transport and hyperbolic phonon polariton cooling renders graphene on BN transistors a valuable nanotechnology for power devices and RF electronics.

中文翻译：

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由双曲衬底冷却的石墨烯齐纳-克莱因晶体管

冷却机制的工程设计是纳米电子学的瓶颈。扩散石墨烯中的热交换主要是由缺陷辅助声子散射引起的，但是六方氮化硼（hBN）上高迁移率石墨烯的情况则大不相同，其中远距离声子对基体的贡献很大。具有局部栅极的hBN晶体管上的双层石墨烯是通过补偿载流子密度降低和高偏压下的齐纳-克莱因隧道效应（ZKT）来实现几乎完美的电流饱和的状态下驱动的。使用噪声测温法，我们表明ZKT触发了新的冷却途径，这是由于超普朗克范围之外的非平衡电子-空穴对在hBN中发射了双曲线声子极化子。