The effect of magnetic and non-magnetic ion damage on the surface state in SmB6

N Wakeham,J Wen,Y.Q Wang,Z Fisk,F Ronning,J.D Thompson

doi:10.1016/j.jmmm.2015.07.045

Abstract

SmB6 is a Kondo insulator with a band structure that is topologically distinct from the vacuum. This is theoretically predicted to produce metallic topological surface states that are robust to perturbations that do not break time reversal symmetry, such as non-magnetic defects. However, the surface state may be destroyed by an impurity with a sufficiently large magnetic moment. In order to test this prediction we show measurements of the resistance of the surface state of single crystals of SmB6 with varying levels of damage induced by magnetic and non-magnetic ion irradiation. We find that at a sufficiently high concentration of damage the surface state reconstructs below an amorphous damaged layer, whether the damage was caused by a magnetic or non-magnetic ion.

Highlights

SmB6 is a known Kondo insulator in which hybridization of the f and conduction electrons opens a small energy gap at the Fermi energy Kasuya (1994)
Note dFeep+einodne-nircreadoifatthioenshdeaemtargeesitsotaenaccehRfasceo.f one t1 is of the SmB6 the depth of crystals damage to the top face of the sample, t2 is the depth of damage to the bottom face
Data from previous work on the e ect of non-magnetic ion damage with Xe and Ar ions are shown in Fig. 2 for comparison

Summary

Introduction

SmB6 is a known Kondo insulator in which hybridization of the f and conduction electrons opens a small energy gap at the Fermi energy Kasuya (1994). This produces a diverging resistivity as temperature decreases, as expected, but the resistivity saturates at around 3 K. At the interface between a topologically non-trivial insulator and the trivial vacuum the energy gap is predicted to close, giving rise to metallic surfaces states on the crystal Ando (2013); Hasan and Kane (2010); Qi and Zhang (2011). The low temperature resistivity saturation in SmB6 was recently shown to be because of metallic states on the surface Syers et al

Methods

Results

Conclusion