Weak-localization magnetoresistance and valley symmetry in graphene
Weak-localization magnetoresistance and valley symmetry in graphene
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DOI：
10.1103/physrevlett.97.146805
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发表时间：
2006-10-06
影响因子：
8.6
通讯作者：
Altshuler, B. L.
中科院分区：
文献类型：
--
作者：
McCann, E.;Kechedzhi, K.;Altshuler, B. L.
由于单层石墨中电子的手征性质（石墨烯）可以预期其中存在弱反定域和正的弱场磁阻。（这破坏了每个谷中费米线的p->-p对称性）抑制了反定域化，而由于实际石墨烯片中原子级尖锐散射体或窄线中的边缘引起的谷间散射倾向于恢复传统的负磁阻我们通过评估石墨烯的磁阻对弛豫速率的依赖性来证明这一点，弛豫速率与打破系统的"隐藏"谷对称性的各种可能方式相关。
Because of the chiral nature of electrons in a monolayer of graphite (graphene) one can expect weak antilocalization and a positive weak-field magnetoresistance in it. However, trigonal warping (which breaks p ->-p symmetry of the Fermi line in each valley) suppresses antilocalization, while intervalley scattering due to atomically sharp scatterers in a realistic graphene sheet or by edges in a narrow wire tends to restore conventional negative magnetoresistance. We show this by evaluating the dependence of the magnetoresistance of graphene on relaxation rates associated with various possible ways of breaking a "hidden" valley symmetry of the system.