Universal crossover in surface superconductivity: Impact of varying Debye energy
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arXiv
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| Auteurs principaux: | , , , |
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866914080915193856 |
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| author | Zhu, Quanyong Luo, Xiaobin Shanenko, A. A. Chen, Yajiang |
| author_facet | Zhu, Quanyong Luo, Xiaobin Shanenko, A. A. Chen, Yajiang |
| contents | Recently, interference-induced surface superconductivity (SC) has been predicted within an attractive Hubbard model with $s$-wave pairing, prompting intensive studies of its properties. The most notable finding is that the surface critical temperature $T_{cs}$ can be significantly enhanced relative to the bulk critical temperature $T_{cb}$. In this work, considering a $1D$ attractive Hubbard model for the half-filling level, we investigate how this enhancement is affected by variations in the Debye energy $\hbarω_D$, which controls the number of states contributing to the pair potential and, in turn, influences the critical temperature. Our study reveals a universal crossover of the surface SC from the weak- to strong-coupling regime, regardless of the specific value of the Debye energy. The location of this crossover is marked by the maximum of $τ= (T_{cs} - T_{cb})/T_{cb}$, which depends strongly on $\hbarω_D$. At its maximum, $τ$ can increase up to nearly $70\%$. Additionally, we examine the evolution of the ratio $Δ_{s0}/k_B T_{cs}$ along the crossover, where $Δ_{s0}$ is the zero-temperature pair potential near the surface (the chain ends), and demonstrate that this ratio can significantly deviate from $Δ_{b0}/k_B T_{cb}$, where $Δ_{b0}$ is the zero-temperature bulk pair potential (in the chain center). Our findings may offer valuable insights into the search for higher critical temperatures in narrow-band superconductors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_22636 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Universal crossover in surface superconductivity: Impact of varying Debye energy Zhu, Quanyong Luo, Xiaobin Shanenko, A. A. Chen, Yajiang Superconductivity Strongly Correlated Electrons Recently, interference-induced surface superconductivity (SC) has been predicted within an attractive Hubbard model with $s$-wave pairing, prompting intensive studies of its properties. The most notable finding is that the surface critical temperature $T_{cs}$ can be significantly enhanced relative to the bulk critical temperature $T_{cb}$. In this work, considering a $1D$ attractive Hubbard model for the half-filling level, we investigate how this enhancement is affected by variations in the Debye energy $\hbarω_D$, which controls the number of states contributing to the pair potential and, in turn, influences the critical temperature. Our study reveals a universal crossover of the surface SC from the weak- to strong-coupling regime, regardless of the specific value of the Debye energy. The location of this crossover is marked by the maximum of $τ= (T_{cs} - T_{cb})/T_{cb}$, which depends strongly on $\hbarω_D$. At its maximum, $τ$ can increase up to nearly $70\%$. Additionally, we examine the evolution of the ratio $Δ_{s0}/k_B T_{cs}$ along the crossover, where $Δ_{s0}$ is the zero-temperature pair potential near the surface (the chain ends), and demonstrate that this ratio can significantly deviate from $Δ_{b0}/k_B T_{cb}$, where $Δ_{b0}$ is the zero-temperature bulk pair potential (in the chain center). Our findings may offer valuable insights into the search for higher critical temperatures in narrow-band superconductors. |
| title | Universal crossover in surface superconductivity: Impact of varying Debye energy |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2410.22636 |