$\textit{Ab Initio}$ Study of Antisite Defects in Nb$_3$Sn: Phase Diagram and Impact on Superconductivity
| Autor: | Sitaraman, Nathan S., Carlson, Jared, Pack, Alden R., Porter, Ryan D., Liepe, Matthias U., Transtrum, Mark K., Arias, Tomás A. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 103, 115106 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.103.115106 |
| Popis: | Antisite defects play a critical role in Nb$_3$Sn superconducting radio frequency (SRF) cavity physics. Such defects are the primary form of disorder in Nb$_3$Sn, and are responsible for stoichiometry variations, including experimentally observed tin-depleted regions within grains and tin-rich regions around grain boundaries. But why they cluster to form regions of different stoichiometries and how they affect the SRF properties of Nb$_3$Sn cavities are not fully understood. Using $\textit{ab initio}$ techniques, we calculate the A15 region of the Nb-Sn phase diagram, discuss a possible modification to the phase diagram near grain boundaries, and calculate $T_c$ as a function of stoichiometry, including experimentally inaccessible tin-rich stoichiometry. We find that the impact of antisite defects on the density of states near the Fermi-level of Nb$_3$Sn plays a key role in determining many of their properties. These results improve our understanding of the obstacles facing Nb$_3$Sn SRF systems, and how modified growth processes might overcome them. Comment: 8 pages, 11 figures |
| Databáze: | arXiv |
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