Re_3W的点接触安德烈夫反射谱研究

本文通过对不同晶体结构Re_3W样品的点接触测量和对比研究,证实具有中心对称结构和非中心对称结构的Re_3W都是弱耦合Bardeen-Cooper-Schrieffer超导体,同时发现在两个相表面都可以形成很理想的点接触结,即电子通过界面时受到的非弹性散射很弱.将Re_3W样品置于大气环境近六个月后重新进行测量,仍然能够得到类似的结果,表明Re_3W具有很好的稳定性. Re_3W的这种优良特性,不仅可通过点接触实验得到的参数推算出Re_3W两个相的费米速度,而且提供了一种简单的方法,可以在点接触实验中利用Re_3W来印证针尖材料的费米速度和测量其自旋极化率等.作为尝试,本文用Re_3W/Ni点接触结测量了铁磁性金属Ni的自旋极化率,得到了与前人报道一致的结果.     

Tip-induced superconductivity commonly existing in the family of transition-metal dipnictides MPn_2

We report the tip-induced superconductivity on the topological semimetal NbSb₂, similar to the observation on TaAs₂ and NbAs₂. Belonging to the same family of MPn₂, all these materials possess similar band structures, indicating that the tip-induced superconductivity may be closely related to their topological nature and share a common mechanism. Further analysis suggests that a bulk band should play the dominant role in such local superconductivity most likely through interface coupling. In addition, the compatibility between the induced superconductivity and tips’ ferromagnetism gives an evidence for its unconventional nature. These results provide further clues to elucidate the mechanism of the tip-induced superconductivity observed in topological materials.