标题： 平坦带热力学在奥托、卡诺和斯特林循环中揭示了性能的增强 显示英文标题

标题： Flat-band thermodynamics reveals enhanced performance across Otto, Carnot, and Stirling cycles

摘要： 魔角扭曲双层石墨烯（MATBG）在外部磁场下表现出显著的电子特性，特别是平坦的朗道能级的出现。 在本研究中，我们对MATBG在三种不同的量子热力学循环下的操作相图进行了全面分析，即量子奥托循环（QOC）、量子卡诺循环（QCC）和量子斯特林循环（QSC）。 使用连续八带模型，我们在多种操作模式下评估了MATBG的热力学性能：热机、制冷机、冷泵和焦耳泵，并将其与其他石墨烯系统进行比较，如单层石墨烯、AB堆叠的双层石墨烯和非魔角扭曲双层石墨烯。 我们的研究结果表明，MATBG在QSC中表现出优越的热机性能，而在QOC中虽然效率较高，但输出功有所减少。 尽管在QOC和QSC中MATBG作为冷泵或制冷机的性能较为一般，但在QCC中作为制冷机表现出显著的改进。 此外，我们在严格的绝热条件下，在QSC和QOC中识别出一种高度可逆的焦耳泵模式，突显了MATBG独特的热力学行为。 显示英文摘要

摘要： Magic-angle twisted bilayer graphene (MATBG) exhibits remarkable electronic properties under external magnetic fields, notably the emergence of flat Landau levels. In this study, we present a comprehensive analysis of MATBG's operational phase diagram under three distinct quantum thermodynamic cycles, i.e., Quantum Otto Cycle (QOC), Quantum Carnot Cycle (QCC), and Quantum Stirling Cycle (QSC). Employing the continuum eight-band model, we evaluate the thermodynamic performance of MATBG across multiple operational modes: heat engine, refrigerator, cold pump, and Joule pump, and benchmark it against other graphene systems such as monolayer graphene, AB-Bernal stacked bilayer graphene, and non-magic-angle twisted bilayer graphene. Our findings reveal that MATBG demonstrates superior heat engine performance in QSC, while achieving high efficiency albeit with reduced work output in QOC. Even though the performance of MATBG as a cold pump or refrigerator is modest in QOC and QSC, it shows notable improvement as a refrigerator in QCC. Additionally, we identify a highly reversible Joule pump mode in both QSC and QOC under strict adiabaticity, underscoring the unique thermodynamic behavior of MATBG.