Destruction of the gap in the intermediate valence compound SmB6 by neutron irradiation

Abstract The electrical resistivity ϱ of a SmB 6 single crystal has been measured during and after a fast neutron irradiation performed at 21 K : for the first time, it is shown that a very low defect concentration destroys the low temperature divergence of ϱ in this compound. These results are considered as an evidence of the existence of an intrinsic gap in pure SmB 6 , and of its destruction by point defects. On the contrary, the irradiation has increased the resistivity value at 300 K, confirming the metallic character of SmB 6 at this temperature. The recovery of defects at 300 K is very weak.