论文标题
强耦合超导与$ t_c $ $ \ sim $ \ sim $ 10.8 k在拓扑半学Mo $ $ _5 $ si $ _3 $中
Strong-Coupling Superconductivity with $T_c$ $\sim$ 10.8 K Induced by P Doping in the Topological Semimetal Mo$_5$Si$_3$
论文作者
论文摘要
通过在拓扑半学Mo $ $ _5 $ si $ _3 $中在SI站点上执行P掺杂，我们发现了Mo $ $ _5 $ _5 $ SI $ _ {3-x} $ p $ _x $ _x $（0.5 $ $ $ $ $ $ $ x $ $ $ \ $ \ $ 2.0）的强耦合超导性。 Mo $ $ _5 $ SI $ _3 $在W $ _5 $ _5 $ si $ _3 $ -Type结构中结晶，带有$ i4/mcm $的空间组（第140号），不是超导体本身。 p掺杂后，晶格参数$ a $减少，而$ c $单调增加。散装超导率以Mo $ _5 $ si $ _ {3-x} $ p $ _x $（0.5 $ \ le $ $ x $ x $ $ \ le $ 2.0）揭示，来自电阻率，磁化和热容量测量。 $ t_c $ in mo $ _5 $ si $ _ {1.5} $ p $ _ {1.5} $达到10.8 K，在W $ _5 $ _3 $ _3 $ -TYPE超导管器中设置新记录。 Mo $ $ _5 $ SI $ _ {1.5} $ P $ _ {1.5} $的上和下关键场分别为14.56 T和105吨。此外，Mo $ _5 $ si $ _ {1.5} $ p $ _ {1.5} $被发现是具有强型电子 - phonon耦合的完全间隙的超导体。第一原理的计算表明，电子 - 音波耦合的增强可能是由于费米水平的变化，这是由电子掺杂引起的。该计算还揭示了Mo $ $ _5 $ si $ _3 $的非平凡带拓扑。 $ t_c $和mo $ $ _5 $ si $ _ {3-x} $ p $ _x $中的上级关键字段在伪化合物中相当高。他们俩都高于NBTI的人，这使未来的应用有望。我们的结果表明，W $ _5 $ SI $ _3 $ -Type化合物是搜索新超导体的理想平台。通过检查其乐队拓扑结构，在这个结构家庭中，可以期望有更多的拓扑超导体候选者。
By performing P doping on the Si sites in the topological semimetal Mo$_5$Si$_3$, we discover strong-coupling superconductivity in Mo$_5$Si$_{3-x}$P$_x$ (0.5 $\le$ $x$ $\le$ 2.0). Mo$_5$Si$_3$ crystallizes in the W$_5$Si$_3$-type structure with space group of $I4/mcm$ (No. 140), and is not a superconductor itself. Upon P doping, the lattice parameter $a$ decreases while $c$ increases monotonously. Bulk superconductivity is revealed in Mo$_5$Si$_{3-x}$P$_x$ (0.5 $\le$ $x$ $\le$ 2.0) from resistivity, magnetization, and heat capacity measurements. $T_c$ in Mo$_5$Si$_{1.5}$P$_{1.5}$ reaches as high as 10.8 K, setting a new record among the W$_5$Si$_3$-type superconductors. The upper and lower critical fields for Mo$_5$Si$_{1.5}$P$_{1.5}$ are 14.56 T and 105 mT, respectively. Moreover, Mo$_5$Si$_{1.5}$P$_{1.5}$ is found to be a fully gapped superconductor with strong electron-phonon coupling. First-principles calculations suggest that the enhancement of electron-phonon coupling is possibly due to the shift of the Fermi level, which is induced by electron doping. The calculations also reveal the nontrivial band topology in Mo$_5$Si$_3$. The $T_c$ and upper critical field in Mo$_5$Si$_{3-x}$P$_x$ are fairly high among pseudobinary compounds. Both of them are higher than those in NbTi, making future applications promising. Our results suggest that the W$_5$Si$_3$-type compounds are ideal platforms to search for new superconductors. By examinations of their band topologies, more candidates for topological superconductors can be expected in this structural family.
