Phase coherent transport in graphene nanoribbons and graphene nanoribbon arrays
Phase coherent transport in graphene nanoribbons and graphene nanoribbon arrays
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DOI：
10.1103/physrevb.86.155403
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发表时间：
2012-10-03
影响因子：
3.7
通讯作者：
Eroms, J.
中科院分区：
文献类型：
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作者：
Minke, S.;Bundesmann, J.;Eroms, J.
我们通过实验研究了在低至20 mK温度下石墨烯纳米带电导率的量子干涉修正，研究了弱局域化（WL）和通用电导波动（ucf）。由于在毫开尔文温度下的单个纳米带中，ucf强烈地掩盖了弱局部化特征，因此我们采用栅极平均和系综平均来抑制ucf。这使我们能够在所有温度下从WL和UCF中提取相相干长度。在1k以上，由于奈奎斯特散射，相相干长度被抑制，而在低温下，我们观察到几百纳米处的相相干长度饱和，超过了条带宽度，但保持在块体石墨烯通常发现的值以下。为了更好地描述高温下的实验，我们扩展了石墨烯中一维（1D）弱局域化的公式，该公式是在强谷间散射的极限下推导出来的，以包括所有弹性散射率。
We have experimentally investigated quantum interference corrections to the conductivity of graphene nanoribbons at temperatures down to 20 mK studying both weak localization (WL) and universal conductance fluctuations (UCFs). Since in individual nanoribbons at milli-Kelvin temperatures the UCFs strongly mask the weak localization feature we employ both gate averaging and ensemble averaging to suppress the UCFs. This allows us to extract the phase coherence length from both WL and UCF at all temperatures. Above 1 K the phase coherence length is suppressed due to Nyquist scattering, whereas at low temperatures we observe a saturation of the phase coherence length at a few hundred nanometers, which exceeds the ribbon width, but stays below values typically found in bulk graphene. To better describe the experiments at elevated temperatures, we extend the formula for one-dimensional (1D) weak localization in graphene, which was derived in the limit of strong intervalley scattering, to include all elastic scattering rates.