AI 中文总结
研究双层石墨烯莫尔超晶格中量子霍尔等态的热输运，用约翰逊噪声测温法测量热导率，发现其以热导量子为单位量子化，仅由陈数决定，确立热导率为拓扑物质探针并为研究奇异相提供途径。
AI 中文摘要
当电子同时受到磁场和周期性势场作用时，会形成分形霍夫施塔特谱，其拓扑能隙包含具有不同陈数的量子霍尔和陈绝缘态。虽然电输运已确定这些态的拓扑结构，但它们的热输运是否同样具有普适性仍未被探索。在此，我们使用约翰逊噪声测温法测量了双层石墨烯 - 六方氮化硼莫尔超晶格中量子霍尔、陈绝缘体和相互作用驱动的对称破缺陈绝缘体态的热导率，该莫尔超晶格的莫尔波长约为14纳米。我们发现热导率（$G_Q$）以热导量子（$G_Q = t\kappa_0T$）为单位进行量子化，且仅由陈数（$t$）决定，与拓扑态的微观起源无关。通过直接揭示霍夫施塔特带中普适的拓扑热输运，我们的工作确立了热导率作为莫尔拓扑物质的严格探针，并为研究包括分数量子霍尔绝缘体在内的更多奇异相提供了途径。
英文摘要
When electrons are subjected simultaneously to a magnetic field and a periodic potential, they form the fractal Hofstadter spectrum, whose topological gaps host quantum Hall and Chern insulating states with distinct Chern numbers. While electrical transport has established the topology of these states, whether their heat transport is likewise universal has remained unexplored. Here, we measure the thermal conductance of quantum Hall, Chern insulator, and interaction-driven symmetry-broken Chern insulator states in a bilayer graphene-hexagonal boron nitride moiré superlattice with a moirè wavelength of $\sim$14 nm using Johnson-noise thermometry. We find that the thermal conductance ($G_Q$) is quantized in units of the thermal conductance quantum ($G_Q = tκ_0T$) and is determined solely by the Chern number ($t$), independent of the microscopic origin of the topological state. By directly revealing universal topological heat transport in Hofstadter bands, our work establishes thermal conductance as a stringent probe of moiré topological matter and provides a route to investigating more exotic phases, including fractional Chern insulators.
Comments4 main figures, supplementary file included
