Observed quantization of anyonic heat flow
Observed quantization of anyonic heat flow
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DOI：
10.1038/nature22052
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发表时间：
2017-05-04
期刊：
影响因子：
64.8
通讯作者：
Umansky, Vladimir
中科院分区：
文献类型：
--
作者：
Banerjee, Mitali;Heiblum, Moty;Umansky, Vladimir
弹道（无碰撞）一维通道的热导量子是一个独特的基本常数1。虽然一维弹道导体的电导的量化早已在实验上建立2，但证明热导的量化一直具有挑战性，因为它需要精确测量非常小的温升。它已经完成了弱相互作用系统的声子（3，4），光子（5）和电子费米液体（6-8）;然而，它在理论上也应该保持在强相互作用系统，如那些分数量子霍尔效应被观察到。这种效应描述了电子分裂成任意子和不带电的准粒子，在某些情况下可以是马约拉纳费米子（2）。因为在分数量子霍尔机制中，体是不可压缩的，所以预计它不会对热导有实质性的贡献，而是由手性一维边缘模式决定。因此，热导率反映了分数量子霍尔电子系统的拓扑性质，电导率的测量无法获得（9-12）。在这里，我们报告测量的热导率在颗粒状（LaughlinJain系列）状态和更复杂的（和较少研究）空穴状的状态在一个高迁移率的二维电子气在GaAs AlGaAs异质结。具有1/2至1的分数朗道能级填充的空穴状态支持下游带电模式以及上游中性模式（13），并且预期具有由其所有下游和上游边缘模式的净手性确定的热导率。我们的结果建立了分数电荷和中性模式的热导量子化的普遍性。任意子热流的测量提供了从电导测量不容易获得的信息。
The quantum of thermal conductance of ballistic (collisionless) onedimensional channels is a unique fundamental constant1. Although the quantization of the electrical conductance of one-dimensional ballistic conductors has long been experimentally established2, demonstrating the quantization of thermal conductance has been challenging as it necessitated an accurate measurement of very small temperature increase. It has been accomplished for weakly interacting systems of phonons(3,4), photons(5) and electronic Fermi liquids(6-8); however, it should theoretically also hold in strongly interacting systems, such as those in which the fractional quantum Hall effect is observed. This effect describes the fractionalization of electrons into anyons and chargeless quasiparticles, which in some cases can be Majorana fermions(2). Because the bulk is incompressible in the fractional quantum Hall regime, it is not expected to contribute substantially to the thermal conductance, which is instead determined by chiral, one-dimensional edge modes. The thermal conductance thus reflects the topological properties of the fractional quantum Hall electronic system, to which measurements of the electrical conductance give no access(9-12). Here we report measurements of thermal conductance in particle-like (LaughlinJain series) states and the more complex (and less studied) hole-like states in a high-mobility two-dimensional electron gas in GaAsAlGaAs heterostructures. Hole-like states, which have fractional Landau-level fillings of 1/2 to 1, support downstream charged modes as well as upstream neutral modes(13), and are expected to have a thermal conductance that is determined by the net chirality of all of their downstream and upstream edge modes. Our results establish the universality of the quantization of thermal conductance for fractionally charged and neutral modes. Measurements of anyonic heat flow provide access to information that is not easily accessible from measurements of conductance.