Transport properties of variously doped SmB₆

Abstract

SmB₆ is a heavy fermion semiconductor with a narrow energy gap at the Fermi level, often denoted also as Kondo insulator, which has recently been considered to be a topological Kondo insulator, the first strongly correlated electron system to exhibit topological surface conduction states. In this contribution we have investigated the electrical transport properties of single crystalline SmB₆ samples having various surfaces, of single crystalline SmB₆ doped with various concentrations of lanthanum, europium, ytterbium and strontium, and of samarium deficient (i.e. doped with metal vacancies) Sm_1-xB₆ sintered samples with the aim to study the influence of miscellaneous doping and sample surfaces on the electronic states in the narrow energy gap of this material. The received results show rather complex resistivity vs. temperature ρ(T) and resistance vs. magnetic field ρ(H) behaviours as a function of wide range La doping and as a function of doping with different elements and vacancies. These results are discussed within the framework of the electronic structure of SmB₆ observed in recent angle resolved photoemission spectroscopy as well as in other (above all transport properties) investigations, which exhibit surface electronic states in the narrow energy gap of this material.

Keywords:

• SmB₆
• topological Kondo insulator
• influence of doping
• transport properties

Acknowledgements

This work was supported by projects [VEGA 2/0032/16], [APVV-14-0605], and by CFNT MVEP project of the Slovak Academy of Sciences. Partial financial support from RAS Program ‘Electron spin resonance, spin-dependent electronic effects and spin technologies’ is acknowledged by V.G. and N.S. The sponsorship of US Steel Kosice is appreciated too.