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arXiv 2202.01796cond-mat.mes-hallcond-mat.str-el
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氮化硼取向石墨烯中竞争电荷密度波、Kekule和反铁磁有序分数量子霍尔态理论

Theory of Competing Charge Density Wave, Kekule and Antiferromagnetic ordered Fractional Quantum Hall states in Graphene aligned with Boron Nitride

Suraj S. Hegde, Inti Sodemann Villadiego

摘要:

我们调查自旋和谷的破缺分数量子霍尔相位内的形式主义,自然扩展的量子霍尔铁磁性的范式从整数到分数量子霍尔状态,使我们能够构建详细的相图的一大类多组分状态。受最近关于石墨烯与氮化硼衬底排列的实验的启发,我们预测了通过增加磁场实现的一系列转变,从亚晶格极化状态开始到谷相干凯库勒电荷密度波状态,并进一步到反铁磁相。此外,填充分数,如$ν=\pm 1/3$,我们预测,该系统在低场发生转变,不仅不同的自旋谷方向的分数填充的味道,但也由其固有的分数量子霍尔性质。这种转变是从一个Laughlin类状态到一个两个组件Halperin类状态都具有电荷密度波序。此外,对于$ν=\pm 1/3,\pm 2/3$,我们预测了一个“倾斜的凯库勒密度相”(CaKD),其中整数和分数占据组件的旋量在谷布洛赫球中具有不同的取向,相反,在中性的整数量子霍尔态的凯库勒态中,两个占据组件在谷布洛赫球中具有相同的取向。

英文摘要:

We investigate spin and valley symmetry-broken fractional quantum Hall phases within a formalism that naturally extends the paradigm of quantum Hall ferromagnetism from integer to fractional quantum Hall states, allowing us to construct detailed phase diagrams for a large class of multi-component states. Motivated by recent experiments on Graphene aligned with a Boron Nitride substrate, we predict a sequence of transitions realized by increasing the magnetic field, starting from a sub-lattice polarized state to a valley coherent Kekule charge density wave state and further to an anti-ferromagnetic phase. Moreover for filling fractions such as $ν=\pm 1/3$, we predict that the system undergoes a transition at low fields, that not only differ by the spin-valley orientation of the fractionally filled flavors but also by their intrinsic fractional quantum Hall nature. This transition is from a Laughlin-like state to a two component Halperin-like state both with a charge density wave order. Moreover for $ν=\pm 1/3,\pm 2/3$, we predict a "canted Kekule density phase"(CaKD) where the spinors of integer and fractionally occupied components have different orientations in the valley Bloch sphere, in contrast to the Kekule state for the integer quantum Hall state at neutrality where both occupied components have the same orientation in the valley Bloch sphere.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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