论文标题
由磁场控制的碳纳米管中的绝缘状态相关
Correlated insulating states in carbon nanotubes controlled by magnetic field
论文作者
论文摘要
我们研究了在几乎金属的曲折碳纳米管中进行竞争的绝缘阶段，在施加的磁通量大约闭合一个山谷中的单个颗粒间隙的条件下。最近的实验表明，在整个磁场上，能量差距持续存在，其中单粒子图片预测隙应关闭并重新打开。使用骨率低的低能量有效理论来描述电子电子相互作用，自旋轨道耦合和磁场之间的相互作用，我们获得了一个相图，该相图由几个竞争性绝缘阶段组成，这些绝缘阶段可以在单个固定间隙闭合点附近形成。我们根据自旋分辨电荷极化密度来表征这些阶段，每个阶段都可以独立地采用与系统的镜像对称性一致的两个可能值之一，或者可以通过自发的镜像对称性破坏过渡来采用中间值。在镜像对称性阶段，轨道磁通量驱动电荷和沿纳米管的自旋电流的绝热变化。我们讨论了这些结果与最近和将来的实验的相关性。
We investigate competing insulating phases in nearly metallic zigzag carbon nanotubes, under conditions where an applied magnetic flux approximately closes the single particle gap in one valley. Recent experiments have shown that an energy gap persists throughout magnetic field sweeps where the single-particle picture predicts that the gap should close and reopen. Using a bosonic low-energy effective theory to describe the interplay between electron-electron interactions, spin-orbit coupling, and magnetic field, we obtain a phase diagram consisting of several competing insulating phases that can form in the vicinity of the single-particle gap closing point. We characterize these phases in terms of spin-resolved charge polarization densities, each of which can independently take one of two possible values consistent with the mirror symmetry of the system, or can take an intermediate value through a spontaneous mirror symmetry breaking transition. In the mirror symmetry breaking phase, adiabatic changes of the orbital magnetic flux drive charge and spin currents along the nanotube. We discuss the relevance of these results to recent and future experiments.
