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arXiv 1602.01039cond-mat.mes-hall
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双层石墨烯中的负库仑阻力

Negative Coulomb Drag in Double Bilayer Graphene

J. I. A. Li, T. Taniguchi, K. Watanabe, J. Hone, A. Levchenko, C. R. Dean

摘要:

平行量子阱之间的库仑阻力提供了一个独特的敏感测量电子相关性,因为阻力响应仅取决于相互作用。最近,已经证明,对于由两个单层石墨烯(MLG)晶体组成的器件,可以获得强相互作用的新机制,所述单层石墨烯(MLG)晶体被几层六方氮化硼隔开。在这里,我们报告了双双层石墨烯(BLG)结构中库仑阻力的测量,与MLG相比,预计相互作用势将进一步增强。在低温和中等密度下,观察到一种新的阻力响应,其符号相反,与以前报道的双MLG中的动量和能量阻力机制不同。我们证明,通过改变装置的长宽比,可以被抑制,并显示出良好的协议与密度和温度依赖性预测的动量阻力在双BLG的响应被发现。我们的结果铺平了道路,追求紧急阶段在强相互作用的双层,如激子凝聚。

英文摘要:

Coulomb drag between parallel quantum wells provides a uniquely sensitive measurement of electron correlations since the drag response depends on interactions only. Recently it has been demonstrated that a new regime of strong interactions can be accessed for devices consisting of two monlolayer graphene (MLG) crystals, separated by few layer hexagonal boron-nitride. Here we report measurement of Coulomb drag in a double bilayer graphene (BLG) stucture, where the interaction potential is anticipated to be yet further enhanced compared to MLG. At low temperatures and intermediate densities a new drag response with inverse sign is observed, distinct from the momentum and energy drag mechanisms previously reported in double MLG. We demonstrate that by varying the device aspect ratio the negative drag component can be suppressed and a response showing excellent agreement with the density and temperature dependance predicted for momentum drag in double BLG is found. Our results pave the way for pursuit of emergent phases in strongly interacting bilayers, such as the exciton condensate.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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