Dirac-electron-mediated magnetic proximity effect in topological insulator/magnetic insulator heterostructures

• Main Authors: Zhao, Weiwei (Author), Garlow, Joseph A. (Author), Wu, Lijun (Author), Zhu, Yimei (Author), Chan, Moses H. W. (Author), Li, Mingda (Contributor), Song, Qichen (Contributor), Liu, Te Huan (Contributor), Moodera, Jagadeesh (Contributor), Chen, Gang (Contributor), Chang, Cui-zu (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Mechanical Engineering (Contributor), Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor), Massachusetts Institute of Technology. Plasma Science and Fusion Center (Contributor), Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology) (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society (APS), 2018-09-06T19:27:06Z.
• Subjects: Article
• Online Access: Get fulltext

 The possible realization of dissipationless chiral edge current in a topological insulator/magnetic insulator heterostructure is based on the condition that the magnetic proximity exchange coupling at the interface is dominated by the Dirac surface states of the topological insulator. Here we report a polarized neutron reflectometry observation of Dirac-electron-mediated magnetic proximity effect in a bulk-insulating topological insulator (Bi0.2Sb0.8)2Te3/magnetic insulator EuS heterostructure. We are able to maximize the proximity-induced magnetism by applying an electrical back gate to tune the Fermi level of topological insulator to be close to the Dirac point. A phenomenological model based on diamagnetic screening is developed to explain the suppressed proximity-induced magnetism at high carrier density. Our work paves the way to utilize the magnetic proximity effect at the topological insulator/magnetic insulator heterointerface for low-power spintronic applications.