Gopinadhan Kalon, Shin Young Jun, Jalil Rashid, Venkatesan Thirumalai, Geim Andre K, Neto Antonio H Castro, Yang Hyunsoo
Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore.
Department of Electrical and Computer Engineering, and NUSNNI-Nanocore, National University of Singapore, Singapore 117576, Singapore.
Nat Commun. 2015 Sep 21;6:8337. doi: 10.1038/ncomms9337.
Understanding magnetoresistance, the change in electrical resistance under an external magnetic field, at the atomic level is of great interest both fundamentally and technologically. Graphene and other two-dimensional layered materials provide an unprecedented opportunity to explore magnetoresistance at its nascent stage of structural formation. Here we report an extremely large local magnetoresistance of ∼2,000% at 400 K and a non-local magnetoresistance of >90,000% in an applied magnetic field of 9 T at 300 K in few-layer graphene/boron-nitride heterostructures. The local magnetoresistance is understood to arise from large differential transport parameters, such as the carrier mobility, across various layers of few-layer graphene upon a normal magnetic field, whereas the non-local magnetoresistance is due to the magnetic field induced Ettingshausen-Nernst effect. Non-local magnetoresistance suggests the possibility of a graphene-based gate tunable thermal switch. In addition, our results demonstrate that graphene heterostructures may be promising for magnetic field sensing applications.
在原子层面理解磁阻，即在外部磁场下电阻的变化，在基础研究和技术应用方面都极具吸引力。石墨烯和其他二维层状材料为在结构形成的初始阶段探索磁阻提供了前所未有的机会。在此，我们报道了在少层石墨烯/氮化硼异质结构中，在400K时局部磁阻极大，约为2000%，在300K、9T外加磁场下非局部磁阻大于90000%。局部磁阻被认为是由垂直磁场作用下少层石墨烯各层间载流子迁移率等大的输运参数差异引起的，而非局部磁阻则是由磁场诱导的埃廷斯豪森 - 能斯特效应导致的。非局部磁阻表明了基于石墨烯的栅极可调热开关的可能性。此外，我们的结果表明石墨烯异质结构在磁场传感应用方面可能很有前景。
