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arXiv · 2209.14636

Influence of electron irradiation on fluctuation conductivity and pseudogap in $YBa_2Cu_3O_{7-δ}$ single crystals

A. L. Solovjov·L. V. Omelchenko·E. V. Petrenko·G. Ya. Khadzhai·D. M. Sergeyev·A. Chroneos·R. V. Vovk
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Abstract

The effect of electron irradiation with the energy of 2.5 MeV on the temperature dependences of the resistivity of an optimally doped $YBa_2Cu_3O_{7-δ}$ single crystal has been studied. The temperature dependences of both fluctuation conductivity $σ^\prime(T)$ and the pseudogap $Δ^*(T)$ on irradiation dose $ϕ$ have been calculated within the local pair model. Here we show that with an increase in $ϕ$, the value of $ρ(300 K)$ increases linearly, while $T_c$ decreases linearly. Concurrently, the value of $ρ{100 K}$ increases nonlinearly, demonstrating a feature for $ϕ_3$ = 4.3 10$^{18}$ e/$cm^2$, which is also observed in the number of other dose-dependent parameters.Regardless of the irradiation dose, in the temperature range from $T_c$ up to $T_{01}$, $σ^\prime(T)$ obeys the classical fluctuation theories of Aslamazov$-$Larkin and Maki$-$Thompson, demonstrating 3D$-$2D crossover with increasing temperature. The crossover temperature $T_0$ makes it possible to determine the coherence length along the $c$-axis, $ξ_c(T)$, which increases by $\approx 3$ times under irradiation. Furthermore, the range of superconducting fluctuations above $T_c$ also noticeably increases.At $ϕ$ = 0, the dependence $Δ^*(T)$ typical for single crystals containing pronounced twin boundaries is observed with a maximum at $T_{pair}$ ~ 120 K and a distinct minimum at $T = T_{01}$. It was determined for the first time that at $ϕ_3$ = 4.3 10$^{18}$ the shape of $Δ^*(T)$ changes strongly and becomes the same as in optimally doped $YBa_2Cu_3O_{7-δ}$ single crystals with a very low pseudogap opening temperature $T^*$ and noticeably reduced $T_{pair}$, while at $T_c(ϕ)$ there are no singularities.

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A. L. Solovjov, L. V. Omelchenko, E. V. Petrenko, G. Ya. Khadzhai, D. M. Sergeyev, A. Chroneos, R. V. Vovk. 2022-09-29. Influence of electron irradiation on fluctuation conductivity and pseudogap in $YBa_2Cu_3O_{7-δ}$ single crystals. https://doi.org/10.1063/10.0013294

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