论文标题
Naalge单晶的精致超导性
Delicate Superconductivity in NaAlGe Single Crystal
论文作者
论文摘要
Nodal-line超导体Naalsi的过渡温度（$ t_c $）为7 K，近年来引起了极大的关注，而其GE对应物Naalge并未超过超导到最低温度，而不管它们相似的原子和电气结构如何。为了应对这种谜，我们求助于Naalge单晶的生长，并表征其半金属基态。有趣的是，当通过氧化掺杂孔时，单晶naalge从半分数转变为超导体（$ t_c = 2.3 \ sim $ 3.5 k），具有零电阻率，并且超过100 $ \％$ $ \％$，但没有热能响应的热能响应。连续的X射线衍射显示出具有较大$ C $轴的瞬态新结构，该结构被认为是由于NA的轻微损失而引起的，并负责脆弱的超导性的出现。我们的发现解决了Naalsi和Naalge的争议，而它们的相似性和差异为研究各种令人兴奋的拓扑量子状态提供了理想的机会。
Nodal-line superconductor NaAlSi with a transition temperature ($T_c$) of 7 K has attracted considerable attention in recent years, whereas its Ge counterpart, NaAlGe, does not superconduct down to the lowest temperature regardless of their similar atomic and electrical structures. To tackle this enigma, we resort to the growth of NaAlGe single crystal and characterize its semimetallic ground state. Interestingly, when hole doped by oxidation, single-crystalline NaAlGe transforms from a semimetal to a superconductor ($T_c = 2.3 \sim$ 3.5 K) with zero resistivity and a diamagnetic shielding fraction over 100$\%$, but without a thermodynamic response in heat capacity. Continuous x-ray diffraction reveals a transient new structure with a larger $c$ axis, which is suggested to have arisen from the minor loss of Na and to be responsible for the emergence of the delicate superconductivity. Our findings resolve the controversies in NaAlSi and NaAlGe, while their similarities and differences provide an ideal opportunity to investigate a variety of exciting topological quantum states.
