School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore.
ACS Nano. 2011 Jul 26;5(7):5490-8. doi: 10.1021/nn200771e. Epub 2011 Jul 8.
We report on the first observation of an anomalous temperature-dependent resistance behavior in coupled Bernal and rhombohedral stacking graphene. At low-temperature regime (<50 K) the temperature-dependent resistance exhibits a drop while at high-temperature regions (>250 K), the resistance increases. In the transition region (50-250 K) an oscillatory resistance behavior was observed. This property is not present in any layered graphene structures other than five-layer. We propose that the temperature-dependent resistance behavior is governed by the interplay of the Coulomb and short-range scatterings. The origin of the oscillatory resistance behavior is the ABCAB and ABABA stacking configurations, which induces tunable bandgap in the five-layer graphene. The obtained results also indicate that a perpendicular magnetic field opens an excitonic gap because of the Coulomb interaction-driven electronic instabilities, and the bandgap of the five-layer graphene is thermally activated. Potentially, the observed phenomenon provides important transport information to the design of few-layer graphene transistors that can be manipulated by a magnetic field.
我们首次观察到了耦合的 Bernal 和三方堆叠石墨烯中异常的温度相关电阻行为。在低温区(<50 K),电阻随温度下降,而在高温区(>250 K),电阻增加。在过渡区(50-250 K),观察到了电阻的振荡行为。这种特性在除了五层以外的任何层状石墨烯结构中都不存在。我们提出,温度相关的电阻行为是由库仑和短程散射的相互作用决定的。电阻的振荡行为源于 ABCAB 和 ABABA 堆叠配置,这在五层石墨烯中诱导了可调谐的能隙。所得结果还表明,由于库仑相互作用驱动的电子不稳定性,垂直磁场会打开激子能隙,并且五层石墨烯的能隙是热激活的。潜在地,观察到的现象为设计可以通过磁场操纵的少层石墨烯晶体管提供了重要的传输信息。