论文标题
二元过渡金属pnictide超导体家族
Family of binary transition metal pnictide superconductors
论文作者
论文摘要
已经研究了过渡金属硝化物（TMN）的超导导性，例如氮化锆（ZRN），具有10 K的超导过渡温度TC。最近，在ZRNX中揭示了ZRNX中的相图具有不同的氮气浓度，与高度机制碳型碳纤维型氧化型非常相似，这非常相似。在这里，我们研究了以面部为中心的立方晶格的TMN，在该晶格中已经获得了ZRN和HFN，并通过第一原则计算预测了八个新的稳定超导体。我们发现CUN具有30 K的高TC，具有非常强的电子 - 音波耦合（EPC）强度。与ZRN相反，CUN在高对称点L处具有软声音，这说明了其更强的EPC。此外，高度对称的结构会导致拓扑受保护的淋巴结点和线，例如KX/Y/Z = 0平面的沙漏Weyl环和Kx/Y/Z =2π/A平面中的Weyl点，以及γ点处的二次带触摸。 CUN可能是拓扑超导体。我们的结果扩大了过渡金属硝酸盐超导体家族，将有助于指导搜索高温拓扑超导体。
Superconductivity in transition metal nitrides (TMNs) has been investigated for a long time, such as zirconium nitride (ZrN) with a superconducting transition temperature Tc of 10 K. Recently, a phase diagram has been revealed in ZrNx with different nitrogen concentrations, which is very similar to that of high-temperature copper oxide superconductors. Here, we study the TMNs with face-centered cubic lattice, where ZrN and HfN have been experimentally obtained, and predict eight new stable superconductors by the first-principle calculations. We find that CuN has a high Tc of 30 K with a very strong electron-phonon coupling (EPC) strength. In contrast to ZrN, CuN has softening acoustic phonons at the high symmetry point L, which accounts for its much stronger EPC. In addition, the highly symmetrical structure leads to topological protected nodal points and lines, such as the hourglass Weyl loop in kx/y/z = 0 plane and Weyl points in kx/y/z = 2π/a plane, as well as quadratic band touch at Γ point. CuN could be a topological superconductor. Our results expand the transition metal nitrides superconductor family and would be helpful to guide the search for high temperature topological superconductors.
