Coexistence of Surface and Bulk Ferromagnetism Mimics Skyrmion Hall Effect in a Topological Insulator

Here, we report the investigation of the anomalous Hall effect in the magnetically doped topological insulator(V,Bi,Sb)2Te3. We find it contains two contributions of opposite sign. Both components are found to depend differently on carrier density, leading to a sign inversion of the total anomalous...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. X 2020-01, Vol.10 (1), p.011012, Article 011012
Main Authors: Fijalkowski, K. M., Hartl, M., Winnerlein, M., Mandal, P., Schreyeck, S., Brunner, K., Gould, C., Molenkamp, L. W.
Format: Article
Language:English
Subjects:
Antimony
Bismuth
Carrier density
Chromium
Doping
Electric potential
Electromagnetism
Ferromagnetic materials
Film thickness
Hypothetical particles
Magnetic fields
Magnetic properties
Magnetism
Magnetization reversal
Particle theory
Phenomenology
Physicists
Quantum Hall effect
Solid state physics
Temperature dependence
Topological insulators
Topology
Voltage
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Here, we report the investigation of the anomalous Hall effect in the magnetically doped topological insulator(V,Bi,Sb)2Te3. We find it contains two contributions of opposite sign. Both components are found to depend differently on carrier density, leading to a sign inversion of the total anomalous Hall effect as a function of applied gate voltage. The two contributions are found to have different magnetization reversal fields, which in combination with a temperature dependent study points towards the coexistence of two ferromagnetic orders in the system. Moreover, we find that the sign of total anomalous Hall response of the system depends on the thickness and magnetic doping density of the magnetic layer. The thickness dependence suggests that the two ferromagnetic components originate from the surface and bulk of the magnetic topological insulator film. We believe that our observations provide insight into the magnetic behavior, and thus will contribute to an eventual understanding of the origin of magnetism in this material class. In addition, our data bear a striking resemblance to anomalous Hall signals often associated with skyrmion contributions. Our analysis provides a straightforward explanation for both the magnetic field dependence of the Hall signal and the observed change in sign without needing to invoke skyrmions, and thus suggest that caution is needed when making claims of effects from skyrmion phases.
ISSN:2160-3308
2160-3308
DOI:10.1103/PhysRevX.10.011012