Electron-phonon coupling, critical temperatures and gaps in $\rm{NbSe_2}$/$\rm{MoS_2}$ Ising Superconductors
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arXiv
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| Formato: | Preprint |
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2024
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| _version_ | 1866910520956682240 |
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| author | Patel, Shubham Jena, Soumyasree Taraphder, A |
| author_facet | Patel, Shubham Jena, Soumyasree Taraphder, A |
| contents | Utilizing Migdal-Eliashberg theory of superconductivity within the first-principles calculations, we work out the role of electron-phonon coupling (EPC) and anisotropic superconducting properties of a recently discovered [Appl. Phys. Lett. 120, 183101 (2022)] 2D van der Waals heterostructure comprising a single layer of MoS$_2$ and few layers of NbSe$_2$. We find strong EPC and a softening of phonon modes in the lowest acoustic branch. While the single MoS$_2$ layer does not actively contribute to the EPC, it significantly elevates the superconducting critical temperature ($T_c$) compared to monolayer NbSe$_2$. This is attributed to the degradation of the charge-density wave (CDW) by the MoS$_2$ layer. Notably, we observe a two-gap superconductivity in $\rm{NbSe_2}$/$\rm{MoS_2}$ and extend our study to three layers of NbSe$_2$. A reduction in $T_c$ with increasing thickness of NbSe$_2$ is observed. We confirm that this trend is consistent with recent experiments, if one goes beyond three layers of NbSe$_2$. We incorporated spin-orbit coupling (SOC) and suggest a possible mechanism for Ising superconductivity. We find that SOC reduces EPC while $T_c$ is suppressed concomitantly by about 5K, leading to a closer estimate of the experimental $T_c$. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2401_02310 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Electron-phonon coupling, critical temperatures and gaps in $\rm{NbSe_2}$/$\rm{MoS_2}$ Ising Superconductors Patel, Shubham Jena, Soumyasree Taraphder, A Superconductivity Materials Science Utilizing Migdal-Eliashberg theory of superconductivity within the first-principles calculations, we work out the role of electron-phonon coupling (EPC) and anisotropic superconducting properties of a recently discovered [Appl. Phys. Lett. 120, 183101 (2022)] 2D van der Waals heterostructure comprising a single layer of MoS$_2$ and few layers of NbSe$_2$. We find strong EPC and a softening of phonon modes in the lowest acoustic branch. While the single MoS$_2$ layer does not actively contribute to the EPC, it significantly elevates the superconducting critical temperature ($T_c$) compared to monolayer NbSe$_2$. This is attributed to the degradation of the charge-density wave (CDW) by the MoS$_2$ layer. Notably, we observe a two-gap superconductivity in $\rm{NbSe_2}$/$\rm{MoS_2}$ and extend our study to three layers of NbSe$_2$. A reduction in $T_c$ with increasing thickness of NbSe$_2$ is observed. We confirm that this trend is consistent with recent experiments, if one goes beyond three layers of NbSe$_2$. We incorporated spin-orbit coupling (SOC) and suggest a possible mechanism for Ising superconductivity. We find that SOC reduces EPC while $T_c$ is suppressed concomitantly by about 5K, leading to a closer estimate of the experimental $T_c$. |
| title | Electron-phonon coupling, critical temperatures and gaps in $\rm{NbSe_2}$/$\rm{MoS_2}$ Ising Superconductors |
| topic | Superconductivity Materials Science |
| url | https://arxiv.org/abs/2401.02310 |