Impurity-generated non-Abelions
Impurity-generated non-Abelions
复制标题
杂质产生的非阿贝尔狮
DOI：
10.1103/physrevb.97.245107
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发表时间：
2017
影响因子：
3.7
通讯作者：
Y. Lyanda
中科院分区：
文献类型：
--
作者：
G. Simion;A. Kazakov;L. Rokhinson;T. Wojtowicz;Y. Lyanda
迄今为止，凝聚态系统中已知两类拓扑超导体和马约拉纳模式：一类是杂质无序强烈抑制拓扑超导带隙并对马约拉纳模式不利，另一类是马约拉纳费米子受到无序鲁棒性超导带隙的保护。在这项工作中，我们预测了第三类拓扑超导和马约拉纳模式，其中它们仅在存在杂质无序的情况下出现。对马约拉纳费米子和其他非阿贝尔离子的观测和控制通常需要对称性，从而导致单粒子光谱中存在间隙。无序将状态引入间隙中，并通过间隙内状态实现电导和邻近感应超导。我们证明，当螺旋畴壁耦合到 s 波超导体时，可以在量子霍尔铁磁体中实现无序拓扑超导。解决了自旋轨道耦合朗道能级系统中杂质束缚态的一般量子力学问题，我们证明了在填充因子 $\nu=2$ 的 CdMnTe 量子阱中量子霍尔铁磁转变的设置中出现无序诱导的马约拉纳模式。最近在该系统中通过静电控制的单畴壁进行的传输实验表明了无序在电导中的重要作用，但留下了一个未解决的问题，即这是否可以从本质上阻止马约拉纳费米子的产生。提出的问题解决方案证明马约拉纳费米子的出现完全是由于杂质无序造成的，开辟了一条前进的道路。我们证明，整数量子霍尔铁磁体中畴壁的静电控制允许操纵马约拉纳模式。分数量子霍尔体系中的铁磁跃迁可以出现类似的物理现象，从而导致高阶非阿贝尔激发的形成和控制。
Two classes of topological superconductors and Majorana modes in condensed matter systems are known to date: one, in which impurity disorder strongly suppresses topological superconducting gap and is detrimental to Majorana modes, and the other, where Majorana fermions are protected by disorder-robust superconductor gap. In this work we predict a third class of topological superconductivity and Majorana modes, in which they appear exclusively in the presence of impurity disorder. Observation and control of Majorana fermions and other non-Abelions often requires a symmetry leading to a gap in a single-particle spectra. Disorder introduces states into the gap and enables conductance and proximity-induced superconductivity via the in-gap states. We show that disorder-enabled topological superconductivity can be realized in a quantum Hall ferromagnet, when helical domain walls are coupled to an s-wave superconductor. Solving a general quantum mechanical problem of impurity bound states in a system of spin-orbit coupled Landau levels, we show that disorder-induced Majorana modes emerge in a setting of the quantum Hall ferromagnetic transition in a CdMnTe quantum wells at a filling factor $\nu=2$. Recent experiments on transport through electrostatically controlled single domain wall in this system indicated the vital role of disorder in conductance, but left an unresolved question whether this could intrinsically preclude generation of Majorana fermions. The proposed resolution of the problem, demonstrating emergence of Majorana fermions exclusively due to impurity disorder, opens a path forward. We show that electrostatic control of domain walls in an integer quantum Hall ferromagnet allows manipulation of Majorana modes. Similar physics can emerge for ferromagnetic transitions in the fractional quantum Hall regime leading to the formation and control of higher order non-Abelian excitations.
影响因子：
3.7
作者：
C. Betthausen;P. Giudici;A. Iankilevitch;C. Preis;V. Kolkovsky;M. Wiater;G. Karcezwski;B.A. Piot;J. Kunc;M. Potemski;T. Wojotowicz;D. Weiss
通讯作者：
D. Weiss