The development of ferromagnetism in Mn-doped Bi2Te3 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 Bi 2-xMnxTe3, 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 Bi 1.96 Mn0.04 Te3 and Bi1.91 Mn 0.09 Te3, a second-order ferromagnetic transition is observed, with TC ∼9-12 K. The easy axis of magnetization in the ferromagnetic phase is perpendicular to the Bi2 Te3 basal plane. Thermoelectric power and Hall effect measurements show that the Mn-doped Bi2Te3 crystals are p -type. Angle-resolved photoemission spectroscopy measurements show that the topological surface states that are present in pristine Bi2 Te3 are also present at 15 K in ferromagnetic Mn-doped Bi2-x MnxTe3 and that the dispersion relations of the surface states are changed in a subtle fashion.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - May 6 2010|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics