Diboride compounds doped with transition metals$\unicode{x2013}$a route to superconductivity through structure stabilization as well as defects
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arXiv
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| Auteurs principaux: | , , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866916336490250240 |
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| author | Dee, P. M. Kim, J. S. Hire, A. C. Lim, J. Fanfarillo, L. Sinha, S. Hamlin, J. J. Hennig, R. G. Hirschfeld, P. J. Stewart, G. R. |
| author_facet | Dee, P. M. Kim, J. S. Hire, A. C. Lim, J. Fanfarillo, L. Sinha, S. Hamlin, J. J. Hennig, R. G. Hirschfeld, P. J. Stewart, G. R. |
| contents | Recent investigations into MoB$_{2}$ have unveiled a direct connection between a pressure-induced structural transition to a P6/mmm space group structure and the emergence of superconductivity, producing critical temperatures up to 32 K at 100 GPa. This pressure-induced superconducting state underscores the potential of doped MoB$_{2}$ as a possible candidate for metastable superconductivity at ambient pressure. In this work, we demonstrate that doping by Zr, Hf, or Ta stabilizes the P6/mmm structure at ambient pressure and results in the realization of a superconducting state with critical temperatures ranging from 2.4 up to 8.5 K depending on the specific doping. We estimate the electron-phonon coupling $λ$ and the density of states based on resistivity and specific heat data, finding that $λ$ ranges from 0.4 - 0.6 for these compounds. Finally, to investigate the role of possible metastable defect structures on the critical temperature, we analyze MoB$_{2}$, MoB$_{2.5}$, and Nb/Zr-doped MoB$_{2}$ using rapid cooling techniques. Notably, splat-quenching produces samples with higher critical temperatures and even retains superconductivity in MoB$_{2}$ at ambient pressure, achieving a critical temperature of 4.5 K. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_03818 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Diboride compounds doped with transition metals$\unicode{x2013}$a route to superconductivity through structure stabilization as well as defects Dee, P. M. Kim, J. S. Hire, A. C. Lim, J. Fanfarillo, L. Sinha, S. Hamlin, J. J. Hennig, R. G. Hirschfeld, P. J. Stewart, G. R. Superconductivity Recent investigations into MoB$_{2}$ have unveiled a direct connection between a pressure-induced structural transition to a P6/mmm space group structure and the emergence of superconductivity, producing critical temperatures up to 32 K at 100 GPa. This pressure-induced superconducting state underscores the potential of doped MoB$_{2}$ as a possible candidate for metastable superconductivity at ambient pressure. In this work, we demonstrate that doping by Zr, Hf, or Ta stabilizes the P6/mmm structure at ambient pressure and results in the realization of a superconducting state with critical temperatures ranging from 2.4 up to 8.5 K depending on the specific doping. We estimate the electron-phonon coupling $λ$ and the density of states based on resistivity and specific heat data, finding that $λ$ ranges from 0.4 - 0.6 for these compounds. Finally, to investigate the role of possible metastable defect structures on the critical temperature, we analyze MoB$_{2}$, MoB$_{2.5}$, and Nb/Zr-doped MoB$_{2}$ using rapid cooling techniques. Notably, splat-quenching produces samples with higher critical temperatures and even retains superconductivity in MoB$_{2}$ at ambient pressure, achieving a critical temperature of 4.5 K. |
| title | Diboride compounds doped with transition metals$\unicode{x2013}$a route to superconductivity through structure stabilization as well as defects |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2310.03818 |