Evolution of the pseudogap temperature dependence in YBa$_2$Cu$_3$O$_{7-δ}$ films under the influence of a magnetic field
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2024
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| author | Petrenko, E. V. Terekhov, A. V. Bludova, L. V. Kolesnichenko, Yu. A. Shytov, N. V. Sergeyev, D. M. Lähderanta, E. Rogacki, K. Solovjov, A. L. |
| author_facet | Petrenko, E. V. Terekhov, A. V. Bludova, L. V. Kolesnichenko, Yu. A. Shytov, N. V. Sergeyev, D. M. Lähderanta, E. Rogacki, K. Solovjov, A. L. |
| contents | The evolution of the temperature dependence of pseudogap $Δ$*(T) in optimally doped (OD) YBa$_2$Cu$_3$O$_{7-δ}$ (YBCO) films with $T_{c}$ = 88.7 K under the influence of a magnetic field $B$ up to 8 T has been studied in detail. It has been established that the shape of $Δ$*(T) for various $B$ over the entire range from the pseudogap opening temperature $T$* to $T_{01}$, below which superconducting fluctuations occur, has a wide maximum at the BEC-BCS crossover temperature $T_{pair}$, which is typical for OD films and untwinned YBCO single crystals. $T$* was shown to be independent on $B$, whereas $T_{pair}$ shifts to the low temperature region along with increase of $B$, while the maximum value of $Δ$*($T_{pair}$) remains practically constant regardless of $B$. It was revealed that as the field increases, the low-temperature maximum near the 3D-2D transition temperature $T_{0}$ is blurred and disappears at $B$ > 5 T. Moreover, above the Ginzburg temperature $T_{G}$, which limits superconducting fluctuations from below, at $B$ > 0.5 T, a minimum appears on $Δ$*(T) at $T_{min}$, which becomes very pronounced with a further increase in the field. As a result, the overall value of $Δ$*(T) decreases noticeably most likely due to pair-breaking affect of a magnetic field. A comparison of $Δ$*(T) near $T_{c}$ with the Peters-Bauer theory shows that the density of fluctuating Cooper pairs actually decreases from <<n$_{\uparrow}$n$_{\downarrow}$>> $\approx$ 0.31 at $B$ = 0 to <<n$_{\uparrow}$n$_{\downarrow}$>> $\approx$ 0.28 in the field 8 T. The observed behavior of $Δ$*(T) around $T_{min}$ is assumed to be due to the influence of a two-dimensional vortex lattice created by the magnetic field, which prevents the formation of fluctuating Cooper pairs near $T_{c}$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_01413 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Evolution of the pseudogap temperature dependence in YBa$_2$Cu$_3$O$_{7-δ}$ films under the influence of a magnetic field Petrenko, E. V. Terekhov, A. V. Bludova, L. V. Kolesnichenko, Yu. A. Shytov, N. V. Sergeyev, D. M. Lähderanta, E. Rogacki, K. Solovjov, A. L. Superconductivity The evolution of the temperature dependence of pseudogap $Δ$*(T) in optimally doped (OD) YBa$_2$Cu$_3$O$_{7-δ}$ (YBCO) films with $T_{c}$ = 88.7 K under the influence of a magnetic field $B$ up to 8 T has been studied in detail. It has been established that the shape of $Δ$*(T) for various $B$ over the entire range from the pseudogap opening temperature $T$* to $T_{01}$, below which superconducting fluctuations occur, has a wide maximum at the BEC-BCS crossover temperature $T_{pair}$, which is typical for OD films and untwinned YBCO single crystals. $T$* was shown to be independent on $B$, whereas $T_{pair}$ shifts to the low temperature region along with increase of $B$, while the maximum value of $Δ$*($T_{pair}$) remains practically constant regardless of $B$. It was revealed that as the field increases, the low-temperature maximum near the 3D-2D transition temperature $T_{0}$ is blurred and disappears at $B$ > 5 T. Moreover, above the Ginzburg temperature $T_{G}$, which limits superconducting fluctuations from below, at $B$ > 0.5 T, a minimum appears on $Δ$*(T) at $T_{min}$, which becomes very pronounced with a further increase in the field. As a result, the overall value of $Δ$*(T) decreases noticeably most likely due to pair-breaking affect of a magnetic field. A comparison of $Δ$*(T) near $T_{c}$ with the Peters-Bauer theory shows that the density of fluctuating Cooper pairs actually decreases from <<n$_{\uparrow}$n$_{\downarrow}$>> $\approx$ 0.31 at $B$ = 0 to <<n$_{\uparrow}$n$_{\downarrow}$>> $\approx$ 0.28 in the field 8 T. The observed behavior of $Δ$*(T) around $T_{min}$ is assumed to be due to the influence of a two-dimensional vortex lattice created by the magnetic field, which prevents the formation of fluctuating Cooper pairs near $T_{c}$. |
| title | Evolution of the pseudogap temperature dependence in YBa$_2$Cu$_3$O$_{7-δ}$ films under the influence of a magnetic field |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2401.01413 |