Observation of Kondo behavior in the single crystals of Mn-doped Bi2Se3 topological insulator

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.