Controlling Electron-Phonon Interactions in Graphene at Ultrahigh Carrier Densities
Controlling Electron-Phonon Interactions in Graphene at Ultrahigh Carrier Densities
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DOI：
10.1103/physrevlett.105.256805
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发表时间：
2010-12-13
影响因子：
8.6
通讯作者：
Kim, Philip
中科院分区：
文献类型：
--
作者：
Efetov, Dmitri K.;Kim, Philip
本文研究了不同载流子密度下石墨烯中电子输运随温度的变化。采用电解栅，我们证明了n可以调整到4 × 10（14）cm（-2）的电子和空穴。测量的样品电阻率ρ在高温极限下随温度T线性增加，表明准经典声子分布是电子散射的原因。随着T减小，电阻率随着rho（T）更快速地减小，类似于T-4。这种低温行为可以通过Bloch-Gruneisen模型来描述，该模型考虑了石墨烯中二维声学声子的量子分布。我们绘制出的密度依赖性的特征温度θ（BG）定义的两个不同的制度之间的交叉，并表明，对于所有的n，ρ（T）尺度作为一个通用的函数的归一化温度T/θ（BG）。
We report on the temperature dependent electron transport in graphene at different carrier densities n. Employing an electrolytic gate, we demonstrate that n can be adjusted up to 4 X 10(14) cm(-2) for both electrons and holes. The measured sample resistivity rho increases linearly with temperature T in the high temperature limit, indicating that a quasiclassical phonon distribution is responsible for the electron scattering. As T decreases, the resistivity decreases more rapidly following rho(T) similar to T-4. This low temperature behavior can be described by a Bloch-Gruneisen model taking into account the quantum distribution of the two-dimensional acoustic phonons in graphene. We map out the density dependence of the characteristic temperature Theta(BG) defining the crossover between the two distinct regimes, and show that, for all n, rho(T) scales as a universal function of the normalized temperature T/Theta(BG).