Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings
Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings
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DOI：
10.1103/physrevb.96.205407
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发表时间：
2017-11-03
影响因子：
3.7
通讯作者：
Stampfer, Christoph
中科院分区：
文献类型：
--
作者：
Dauber, Jan;Oellers, Martin;Stampfer, Christoph
我们目前的低温磁输运测量石墨烯环封装在六方氮化硼。我们研究了硬约束准弹道石墨烯环中的相位相干输运，并显示了Aharonov-Bohm（AB）振荡。特别是，我们报告的观察H/E，H/2 E和H/3E电导振荡。此外，我们显示签名的磁聚焦效应在小磁场确认弹道输运。我们进行紧束缚计算，使我们能够再现我们实验发现的所有重要特征，并使我们能够更深入地理解底层物理。最后，我们报告在合理的高磁场下，在量子霍尔制度中的AB电导振荡的观察，在那里我们发现具有增强的AB振荡可见度的值高达0.7%的区域。这些振荡很好地解释了考虑到允许硬壁和软壁限制共存的无序。
We present low-temperature magnetotransport measurements on graphene rings encapsulated in hexagonal boron nitride. We investigate phase-coherent transport and show Aharonov-Bohm (AB) oscillations in quasiballistic graphene rings with hard confinement. In particular, we report on the observation of h/e, h/2e, and h/3e conductance oscillations. Moreover we show signatures of magnetic focusing effects at small magnetic fields confirming ballistic transport. We perform tight-binding calculations which allow us to reproduce all significant features of our experimental findings and enable a deeper understanding of the underlying physics. Finally, we report on the observation of the AB conductance oscillations in the quantum Hall regime at reasonable high magnetic fields, where we find regions with enhanced AB oscillation visibility with values up to 0.7%. These oscillations are well explained by taking disorder into account allowing for a coexistence of hard-and soft-wall confinement.