Alavirad Yahya, Clarke David, Nag Amit, Sau Jay D
Department of Physics, Condensed Matter Theory Center and the Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA.
Phys Rev Lett. 2017 Nov 24;119(21):217701. doi: 10.1103/PhysRevLett.119.217701. Epub 2017 Nov 20.
Parafermionic zero modes are a novel set of excitations displaying non-Abelian statistics somewhat richer than that of Majorana modes. These modes are predicted to occur when nearby fractional quantum Hall edge states are gapped by an interposed superconductor. Despite substantial experimental progress, we argue that the necessary crossed Andreev reflection in this arrangement is a challenging milestone to reach. We propose a superconducting quantum dot array structure on a fractional quantum Hall edge that can lead to parafermionic zero modes from coherent superconducting forward scattering on a quantum Hall edge. Such coherent forward scattering has already been demonstrated in recent experiments. We show that for a spin-singlet superconductor interacting with loops of spin unpolarized 2/3 fractional quantum edge, even an array size of order 10 should allow one to systematically tune into a parafermionic degeneracy.
准费米子零模是一组新型激发态，其展示出的非阿贝尔统计特性比马约拉纳模的更为丰富。预计当附近的分数量子霍尔边缘态被插入的超导体能隙化时会出现这些模式。尽管在实验上取得了重大进展，但我们认为在这种配置中实现必要的交叉安德烈夫反射是一个具有挑战性的里程碑。我们提出了一种基于分数量子霍尔边缘的超导量子点阵列结构，它可通过量子霍尔边缘上的相干超导前向散射产生准费米子零模。这种相干前向散射已在近期实验中得到证实。我们表明，对于与自旋非极化的2/3分数量子边缘的回路相互作用的自旋单重态超导体，即使阵列尺寸为10左右，也应能让人们系统地调谐到准费米子简并态。
