论文标题
石墨烯中的量子大厅谷拆分器和可调的马赫·泽尔德干涉仪
Quantum Hall valley splitters and tunable Mach-Zehnder interferometer in graphene
论文作者
论文摘要
石墨烯是电子量子光学领域非常有前途的测试床。但是，仍然缺少完全可调和相干的电子束分离器。我们报告了石墨烯中电子束拆分器的演示，表明夫妇量子厅边缘通道具有相反的山谷极化。我们的光束拆分器的电子传输可以从零调整到接近统一。通过独立将光束拆分器设置在石墨烯PN连接的两个角以进行中间变速器，我们实现了完全可调的电子马赫Zhhnder干涉仪。这种可调节性使我们能够明确识别由于马赫德干涉仪而引起的量子干扰，并研究了它们与梁切口传输和干涉仪偏置电压的依赖性。与常规半导体干涉仪的比较表明，在这两个不同的2D系统中驱动量子反应性的通用过程，石墨烯对它们的效果更为强大。
Graphene is a very promising test-bed for the field of electron quantum optics. However, a fully tunable and coherent electronic beam splitter is still missing. We report the demonstration of electronic beam splitters in graphene that couple quantum Hall edge channels having opposite valley polarizations. The electronic transmission of our beam splitters can be tuned from zero to near unity. By independently setting the beam splitters at the two corners of a graphene PN junction to intermediate transmissions, we realize a fully tunable electronic Mach-Zehnder interferometer. This tunability allows us to unambiguously identify the quantum interferences due to the Mach-Zehnder interferometer, and to study their dependence with the beam-splitter transmission and the interferometer bias voltage. The comparison with conventional semiconductor interferometers points towards universal processes driving the quantum decoherence in those two different 2D systems, with graphene being much more robust to their effect.
