Department of Physics, Columbia University, New York, 10027 New York, USA.
Department of Applied Physics and Applied Mathematics, Columbia University, New York, 10027 New York, USA.
Phys Rev Lett. 2019 Jan 18;122(2):026802. doi: 10.1103/PhysRevLett.122.026802.
We report experimental observation of the reentrant integer quantum Hall effect in graphene, appearing in the N=2 Landau level. Similar to high-mobility GaAs/AlGaAs heterostructures, the effect is due to a competition between incompressible fractional quantum Hall states, and electron solid phases. The tunability of graphene allows us to measure the B-T phase diagram of the electron solid phase. The hierarchy of reentrant states suggests spin and valley degrees of freedom play a role in determining the ground state energy. We find that the melting temperature scales with magnetic field, and construct a phase diagram of the electron liquid-solid transition.
我们报告了在石墨烯中观察到的重入整数量子霍尔效应的实验结果，该效应出现在 N=2 朗道能级中。与高迁移率 GaAs/AlGaAs 异质结构类似，该效应是由于不可压缩分数量子霍尔态和电子固态相之间的竞争引起的。石墨烯的可调谐性使我们能够测量电子固态相的 B-T 相图。重入态的层次结构表明，自旋和谷自由度在确定基态能量方面起着作用。我们发现，熔化温度与磁场成正比，并构建了电子液-固相变的相图。
