Intermediate scattering potential strength in electron-irradiated YBa₂Cu₃O_7-δ from London penetration depth measurements

Journal Article · 24 January 2022 · Physical Review. B

DOI: https://doi.org/10.1103/physrevb.105.014514 · OSTI ID:1856832

Cho, Kyuil  ^[1]; Kończykowski, M.  ^[2]; Teknowijoyo, S.  ^[1]; Ghimire, S.  ^[1]; Tanatar, M. A.  ^[1]; Mishra, Vivek  ^[3]; Prozorov, R.  ^[1]

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1. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
2. Ecole Polytechnique, Palaiseau (France)
3. Chinese Academy of Sciences (CAS), Beijing (China). Kavli Institute for Theoretical Sciences

Temperature-dependent London penetration depth, λ(T), of a high quality optimally-doped YBa₂Cu₃O_7-δ single crystal was measured using tunnel-diode-resonator technique. Controlled artificial disorder was induced by low-temperature 20 K irradiation by 2.5 MeV electrons at two large doses of 3.8 x 10¹⁹ and 5.3 x 10¹⁹ electrons per cm². The irradiation caused significant suppression of the superconductor's critical temperature, T_c, from 94.6 K to 90.0 K, and to 78.7 K, respectively. The low-temperature behavior of λ(T) evolves from a T-linear in pristine state to a T² behavior after irradiation, expected for a line-nodal d-wave superconductor. However, the original theory that explained such behavior assumed a unitary limit of the scattering potential, whereas usually in normal metals and semiconductors, Born scattering is sufficient to describe the experiment. To estimate the scattering potential strength, we calculated the superfluid density, ρ_s (t = T/T_c) = λ² (0)/λ² (T), varying the amount and strength of non-magnetic scattering using a self-consistent t-matrix theory. Fitting the obtained curves to a power law, ρ_s = 1 - Rtⁿ, and to a polynomial, ρ_s = 1 - At - Bt², and comparing the coefficients n in one set and A and B in another with the experimental values, we estimate the phase shift to be around 70 and 65°, respectively. We correlate this result with the evolution of the density of states with nonmagnetic disorder.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: Chinese Academy of Sciences; NSFC; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1856832
• Report Number(s): IS-J--10,741; 11674278; XDB28000000
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 1 Vol. 105; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English