Abstract
The Bi2Se3 and Mn doped Bi2Se3 (i.e. Bi1.5Mn0.5Se3, referred as BiMnSe) single crystals were grown using a melt growth method and characterized for their structural, electrical and magnetic properties. These crystals were found to be of single phase having rhombohedral structure with the space group (R3¯m). The magnetoresistance measurements have been carried out in the temperature range 5-50 K, under magnetic fields up to 8 T. The variation of resistivity with temperature shows the Metallic behavior in case of Bi2Se3, and up-turn at low temperatures in the BiMnSe. Metallic behavior was observed up to T > 40 K, whereas below 40K, Kondo effect has been observed. A saturating resistance upturn at low temperatures is observed in the BiMnSe, indicating the presence of Kondo effect due to the existence of localized impurity spins. While the Bi2Se3 is diamagnetic, the BiMnSe is in ferromagnetic state at 5 K. This study opens up a new direction to investigate the physics and device applications of magnetically tunable topological insulators.
Highlights
Topological insulators (TIs) are the materials which selectively exhibit an insulating behavior in the bulk but are conducting at the surface.[1,2] The spin–orbit coupling in the materials leads to the formation of surface states on their edge or surface that are topologically protected from scattering
Many studies showed that long-range magnetic order can be formed in TIs when these are cooperated with transition metals, characterized at the nanoscale by scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) measurements of the effects of doping on the surface states
This systematic crystal structure change was observed in the system and such crystalline ordered quintuple layered system can be helpful for the determination of topological surface state and for different properties
Summary
The doping of Cr has been predicted to lead to an insulating ferromagnetic ground state in Bi2Se3,17,32 as is required for the QAH effect, whereas Mn and Fe doping leads to a metallic state.[37] Many studies showed that long-range magnetic order can be formed in TIs when these are cooperated with transition metals, characterized at the nanoscale by scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) measurements of the effects of doping on the surface states.
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