Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, United States.
Nano Lett. 2011 Sep 14;11(9):3624-8. doi: 10.1021/nl201430a. Epub 2011 Aug 3.
We investigate the magnetotransport properties of quasi-free-standing epitaxial graphene bilayer on SiC, grown by atmospheric pressure graphitization in Ar, followed by H(2) intercalation. At the charge neutrality point, the longitudinal resistance shows an insulating behavior, which follows a temperature dependence consistent with variable range hopping transport in a gapped state. In a perpendicular magnetic field, we observe quantum Hall states (QHSs) both at filling factors (ν) multiples of four (ν = 4, 8, 12), as well as broken valley symmetry QHSs at ν = 0 and ν = 6. These results unambiguously show that the quasi-free-standing graphene bilayer grown on the Si-face of SiC exhibits Bernal stacking.
我们研究了在 Ar 气氛中通过常压石墨化生长、随后进行 H(2)插层的 SiC 上准自由站立外延双层石墨烯的磁输运性质。在电荷中性点，纵向电阻表现出绝缘行为，其温度依赖性符合能隙状态中的变程跳跃输运。在垂直磁场中，我们观察到填充因子（ν）为 4、8、12 的整数倍的量子霍尔态（QHS），以及 ν = 0 和 ν = 6 的破谷对称 QHS。这些结果明确表明，在 SiC 的 Si 面上生长的准自由站立石墨烯双层表现出 Bernal 堆叠。
