Anomalous electron-electron interactions in epitaxial graphene on SiC
Anomalous electron-electron interactions in epitaxial graphene on SiC
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DOI：
10.1016/j.carbon.2021.08.028
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发表时间：
2021-10
期刊：
影响因子：
10.9
通讯作者：
Yue Yang;K. Gao;W. Wang;Guiri Yu;Yuna Sun;X. Zhang;Zeyu Li
中科院分区：
文献类型：
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作者：
Yue Yang;K. Gao;W. Wang;Guiri Yu;Yuna Sun;X. Zhang;Zeyu Li
电子-电子相互作用(EEI)对二维系统中载流子的输运行为起着至关重要的作用。在传统的二维体系中，相互作用的强度可以通过改变载流子浓度来调节，而在具有线性色散关系的单层石墨烯中，由于相互作用参数与载流子浓度无关，因此无法控制相互作用的强度。在这里，在外延石墨烯中观察到了反常的载流子浓度依赖关系。通过量子输运测量，得到了霍尔系数与温度的对数关系，这是EEI的一个表现形式。从对数温度依赖关系中提取与EEI相关的因子Ke e。出乎意料的是，提取的Ke e随载流子浓度的增加而增加，通过对Drude电导率的对数校正分析进一步证实了这一点。这可以归因于气体吸收引起的费米-液体常数F0EEI与载流子浓度的依赖关系，这为控制石墨烯中的σ提供了一条途径。
Electron-electron interactions (EEI) play a pivotal role in the transport behavior of carriers confined in a two-dimensional system. The strength of the interaction can be tuned by changing carrier concentration in a conventional two-dimensional system, while it expectedly cannot be controlled in monolayer graphene with a linear dispersion relation since the interaction parameter is not related to carrier concentration. Here, an anomalous carrier-concentration dependence of the EEI is observed in epitaxial graphene on SiC. From quantum transport measurement, a logarithmic temperature dependence of the Hall coefficient is obtained, which is a manifestation of the EEI. From the logarithmic temperature dependence, the EEI-related factor K e e is extracted. Unexpectedly, the extracted K e e shows an increase on increasing carrier concentration, which is further confirmed by analyzing logarithmic correction to the Drude conductivity. This can be attributed to the carrier-concentration dependence of Fermi-liquid constant F 0 σ due to gas absorption, which offers a route to control the EEI in graphene.