外延石墨烯中量子霍尔效应破裂的相空间。

Phase space for the breakdown of the quantum Hall effect in epitaxial graphene.

机构信息

Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.

出版信息

Phys Rev Lett. 2013 Aug 30;111(9):096601. doi: 10.1103/PhysRevLett.111.096601. Epub 2013 Aug 27.

DOI:10.1103/PhysRevLett.111.096601

Abstract

We report the phase space defined by the quantum Hall effect breakdown in polymer gated epitaxial graphene on SiC (SiC/G) as a function of temperature, current, carrier density, and magnetic fields up to 30 T. At 2 K, breakdown currents (I(c)) almost 2 orders of magnitude greater than in GaAs devices are observed. The phase boundary of the dissipationless state (ρ(xx)=0) shows a [1-(T/T(c))2] dependence and persists up to T(c)>45 K at 29 T. With magnetic field I(c) was found to increase ∝B(3/2) and T(c)∝B2. As the Fermi energy pproaches the Dirac point, the ν=2 quantized Hall plateau appears continuously from fields as low as 1 T up to at least 19 T due to a strong magnetic field dependence of the carrier density.

摘要

我们报告了在 SiC 上聚合物门控外延石墨烯（SiC/G）中量子霍尔效应击穿的相空间，作为温度、电流、载流子密度和磁场的函数，磁场高达 30 T。在 2 K 时，观察到击穿电流（I(c)）比 GaAs 器件大 2 个数量级。无耗散状态（ρ(xx)=0）的相边界表现出[1-(T/T(c))2]的依赖性，并在 29 T 时持续到 T(c)>45 K。随着磁场的增加，发现 I(c)∝B(3/2)，T(c)∝B2。随着费米能接近狄拉克点，由于载流子密度对磁场的强烈依赖性，ν=2 量子霍尔平台从低至 1 T 的磁场连续出现，至少到 19 T。