Electrically Controllable Surface Magnetism on the Surface of Topological Insulators

We study the Ruderman-Kittle-Kasuya-Yosida (RKKY) interaction in a monolayer MoS2. We show that the rotation of the itinerant electron spin due to the spin-orbit coupling causes a twisted interaction between two magnetic adatoms which consists of different RKKY coupling terms, the Heisenberg, Dzyaloshinsky-Moriya and Ising interactions. We find that the interaction terms are very sensitive to the Fermi energy values and change dramatically from doped to undoped systems. A finite doping causes that all parts of the interaction oscillate with the distance of two magnetic impurities, R and the interaction behaves like R −2 for the long distance between two localized spins. We explore a beating pattern of oscillations of the RKKY interaction which occurs for the doped system.

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“…This phenomena is the same behavior which occurs in the topological insulators when the Fermi energy lies in a gap 22 . Fig.…”

Section: Numerical Resultsmentioning

confidence: 55%

Indirect exchange interaction between magnetic adatoms in monolayer MoS2

2013

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“…Because of the linear energy spectrum of surface Dirac fermions, the RKKY coupling does not have conventional FM/AFM oscillations when the Fermi level is tuned close to the Dirac point. This occurs because the Fermi wavelength λ F = 1/k F is much larger than the average distance between neighboring magnetic impurities [91,92]; this effect smoothes out the coupling coefficient compared with conventional dilute magnetic semiconductors (DMS). The TI surface-mediated RKKY interaction will thus minimize local magnetic moment disorders and produce much more robust ferromagnetism.…”

Section: Spintronics Devicesmentioning

confidence: 99%

Review of 3D topological insulator thin‐film growth by molecular beam epitaxy and potential applications

Kou

Wang

2013

Physica Rapid Research Ltrs

151

152

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Abstractmagnified imageThin films of V–VI compound semiconductors (Bi2Se3, Bi2Te3 and Sb2Te3) have been synthesized recently as three‐dimensional topological insulators (TIs). Although these materials have been used as thermoelectric materials for many years, for future studies and applications of the topological surface states, a major bottleneck remains the lack of high‐quality bulk materials that have very few defects and the Fermi level can be moved to inside the bulk bandgap. In this paper, we review the use of molecular beam epitaxy (MBE) technique to achieve high‐quality TI materials. Furthermore, the use of layered growth in MBE affords us the fabrication of heterostructures, such as quantum wells and superlattices. Thus, it may further enable additional studies and applications, similar to those of conventional semiconductor heterostructures but with the novel properties of TI. We explore the growth mechanism, providing a detail discussion on the growth parameters of thin‐film synthesis by MBE. Then we discuss more complex cases, such as functional doping, heterostructures and superlattices. Potential new properties in such quantum structures are discussed. Finally, we give an outlook on this material system for both fundamental studies and applications. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…In particular, controllable surface magnetism and its interaction with itinerant electrons in a non-magnetic host has formed the subject of continuous investigations [1][2][3][4] . In a series of comparative experiments, we study the interactions which electrons in the accumulation layer formed on the InAs surface experience from local spin moments due to rare earth (RE) ions located on the surface, upon deposition of an aqueous RE nitrate solution.…”

mentioning

confidence: 99%