Semiconductor-insulator transition in a YbB6 nanowire with boron vacancy

In this paper, we report the study of transport and magnetic properties of ytterbium hexaboride (YbB6) nanowires grown by a low trigger-temperature (200-240 degrees C) solid state method. The temperature dependence of resistivity shows that the YbB6 nanowire undergoes a semiconductor-insulator transition (SIT) below 20 K with an activation energy Delta E of 1 meV. The value of p at 2 K reaches 49 times the value of p at 300 K (p(2K)/p(300K) = 49). The observed non-saturating magnetoresistance (MR) has a linear relationship with B-2. The anomalous electronic transport in the YbB6 nanowire can be explained by the mixed valence of Yb ions due to the boron deficiency supporting by the X-ray photoelectron spectroscopy (XPS) and paramagnetic magnetization.