Huang Lung-I, Yang Yanfei, Elmquist Randolph E, Lo Shun-Tsung, Liu Fan-Hung, Liang Chi-Te
National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; Department of Physics, National Taiwan University, Taipei 106, Taiwan.
National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; Department of Physics, Georgetown University, Washington, DC 20057, USA.
RSC Adv. 2016;6(76):71977-71982. doi: 10.1039/C6RA07859A. Epub 2016 Jul 22.
We report on magneto-transport measurements on low-density, large-area monolayer epitaxial graphene devices grown on SiC. We observe temperature ()-independent crossing points in the longitudinal resistivity ρ, which are signatures of the insulator-quantum Hall (I-QH) transition, in all three devices. Upon converting the raw data into longitudinal and Hall conductivities σ and σ, in the most disordered device, we observed -driven flow diagram approximated by the semi-circle law as well as the -independent point in near /. We discuss our experimental results in the context of the evolution of the zero-energy Landau level at low magnetic fields . We also compare the observed strongly insulating behaviour with metallic behaviour and the absence of the I-QH transition in graphene on SiO prepared by mechanical exfoliation.
我们报告了在碳化硅（SiC）上生长的低密度、大面积单层外延石墨烯器件的磁输运测量结果。在所有三个器件中，我们观察到纵向电阻率ρ中与温度（）无关的交叉点，这是绝缘体 - 量子霍尔（I - QH）转变的特征。在将原始数据转换为纵向和霍尔电导率σ和σ后，在最无序的器件中，我们观察到由半圆定律近似的驱动流程图以及在接近/时σ中的与无关点。我们在低磁场下零能量朗道能级的演化背景下讨论了我们的实验结果。我们还将观察到的强绝缘行为与金属行为以及通过机械剥离制备的SiO上石墨烯中不存在I - QH转变进行了比较。
