Controllable synthesis of Gd-doped SmB6 nanobelt arrays for modulating their surface transport behaviors

Abstract

Samarium hexaboride (SmB6) nanobelts are believed as better platforms to study the interaction between strongly correlated electron states and topological states than their bulk topological Kondo insulator (TKI) counterparts because they have more abundant surface states. To date, there are few reports focused on the modulation of surface transport behaviors of SmB6 nanobelts because of the absence of high-quality controllable synthesis and doping techniques, despite which is very essential for their future applications. In this paper, the undoped and Gd-doped SmB6 nanobelt arrays have been successfully fabricated on the Si substrate by a one-step co-evaporation method. Both of the undoped and Gd-doped nanobelts were indexed as single-crystalline cubic structures with a growth direction of [110]. The results show that the low-temperature resistivity of the Gd-doped SmB6 nanobelts becomes unsaturated when the magnetic Gd content is increased to about 2.0 at.%. Different from the undoped SmB6 nanobelts, the extraordinary non-linear behaviors of the Hall resistivity–temperature curves are firstly found in the Gd-doped SmB6 nanobelts, attributing to the anomalous Hall effect (AHE). Both the breaking of the surface time-reversal symmetry of the SmB6 nanobelts and the resultant magnetism by the Gd doping are suggested to be responsible for the occurrence of the AHE. Our study may shed light on comprehending the interaction between correlated electron states and topological surface states in TKI nanostructures and modulating their surface transport behaviors for future quantum information applications.