Berlin 2024 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 18: Superconductivity: Poster

TT 18.17: Poster

Montag, 18. März 2024, 15:00–18:00, Poster C

Strain-induced structural change and diffuse scattering in HgBa₂CuO_4.09 — •Mai Ye¹, Wenshan Hong², Tom Lacmann¹, Mehdi Frachet¹, Igor Vinograd¹, Gaston Garbarino³, Sofia-Michaela Souliou¹, Amir-Abbas Haghighirad¹, Yuan Li², and Matthieu Le Tacon¹ — ¹Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany — ²International Center for Quantum Materials, School of Physics, Peking University, 100871 Beijing, China — ³European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France

We study the structural change and diffuse scattering induced by a-axis compressive strain in HgBa₂CuO_4.09 at T_c = 78 K, using synchrotron X-ray diffraction. The high-temperature superconductor exhibits negative Poisson ratio below 0.6% strain. Although the c-axis lattice parameter at 1% strain is 0.1% larger than its zero-strain value, the Cu-O bond length is 1.2% shorter than the zero-strain value. Strain-induced diffuse scattering appears at the two sides of Bragg peaks along the strain direction. Such diffuse scattering has a wavenumber of (0.5,0,0), corresponding to a modulation with a period of twice the a-axis lattice parameters. The diffuse-scattering features saturate at 0.2% strain and exhibit little change on cooling below T_c.

Keywords: high-temperature superconductor; cuprate; x-ray; strain; diffuse scattering