Abstract
The development of ferromagnetism in Mn-doped is characterized through measurements on a series of single crystals with different Mn content. Scanning tunneling microscopy analysis shows that the Mn substitutes on the Bi sites, forming compounds of the type , and that the Mn substitutions are randomly distributed, not clustered. Mn doping first gives rise to local magnetic moments with Curie-like behavior, but by the compositions and , a second-order ferromagnetic transition is observed, with . The easy axis of magnetization in the ferromagnetic phase is perpendicular to the basal plane. Thermoelectric power and Hall effect measurements show that the Mn-doped crystals are -type. Angle-resolved photoemission spectroscopy measurements show that the topological surface states that are present in pristine are also present at 15 K in ferromagnetic Mn-doped and that the dispersion relations of the surface states are changed in a subtle fashion.
6 More- Received 26 January 2010
DOI:https://doi.org/10.1103/PhysRevB.81.195203
©2010 American Physical Society
Synopsis
A dilute magnetic topological semiconductor?
Published 10 May 2010
By doping the topological insulator with magnetic manganese, researchers have turned it into a dilute ferromagnetic semiconductor.
See more in Physics