Electrostatic control of quantum Hall ferromagnetic transition: A step toward reconfigurable network of helical channels
Electrostatic control of quantum Hall ferromagnetic transition: A step toward reconfigurable network of helical channels
复制标题
DOI：
10.1103/physrevb.94.075309
复制
发表时间：
2016-08-24
影响因子：
3.7
通讯作者：
Rokhinson, Leonid P.
中科院分区：
文献类型：
--
作者：
Kazakov, Aleksandr;Simion, George;Rokhinson, Leonid P.
通过改变倾斜磁场实验中回旋加速器和塞曼能量的比率，可以研究固定填充因子下不同极化的量子霍尔态之间的铁磁跃迁。然而，在固定磁场下局部控制这种转变的能力将开启一系列有吸引力的应用，例如，在二维平面中形成一维螺旋畴壁的可重构网络。与超导体耦合，这种畴壁可以支持非阿贝尔激励。在本文中，我们报告了异质结构的发展，其中量子霍尔铁磁（QHFm）转变可以通过静电门控进行局部控制。通过顺磁性 Mn 杂质的设计放置，在 CdTe 量子阱中形成高迁移率二维电子气。栅极感应静电场使电子波函数沿生长方向移动，并改变量子阱中的电子与 Mn 上 d 壳层电子之间的重叠，从而控制 s-d 交换相互作用和 QHFm 跃迁场。所证明的 QHFm 跃迁在填充因子 nu = 2 下的偏移足够大，足以在固定磁场下完全控制自旋极化。
Ferromagnetic transitions between quantum Hall states with different polarization at a fixed filling factor can be studied by varying the ratio of cyclotron and Zeeman energies in tilted magnetic field experiments. However, an ability to locally control such transitions at a fixed magnetic field would open a range of attractive applications, e.g.,formation of a reconfigurable network of one-dimensional helical domain walls in a two-dimensional plane. Coupled to a superconductor, such domain walls can support non-Abelian excitations. In this paper we report development of heterostructures where quantum Hall ferromagnetic (QHFm) transition can be controlled locally by electrostatic gating. A high mobility two-dimensional electron gas is formed in CdTe quantum wells with engineered placement of paramagnetic Mn impurities. A gate-induced electrostatic field shifts the electron wave function in the growth direction and changes an overlap between electrons in the quantum well and d-shell electrons on Mn, thus controlling the s-d exchange interaction and the field of the QHFm transition. The demonstrated shift of the QHFm transition at a filling factor nu = 2 is large enough to allow full control of spin polarization at a fixed magnetic field.