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TT: Fachverband Tiefe Temperaturen
TT 68: Superconductivity: Properties and Electronic Structure
TT 68.2: Talk
Thursday, March 21, 2024, 09:45–10:00, H 3010
Annealing Tl2Ba2CuO6+δ - a step towards the origin of cuprate superconductivity — •Ayanesh Maiti1,2,3, Seunghyun Khim1, Carsten Putzke2, Philip Moll2, and Andrew Mackenzie1,3 — 1MPI for Chemical Physics of Solids, Dresden, Germany — 2MPI for Structure and Dynamics of Matter, Hamburg, Germany — 3University of St Andrews, St Andrews, Scotland
Cuprate superconductors have attracted a lot of attention due to their high Tc’s that can reach up to 130 K in ambient pressure. However, the physics underlying their properties has remained obscured by (i) multitudes of complex orders that appear near the superconducting phase, and (ii) the inseparable effects of the disorder that is introduced as they are doped.
Decades of past research have identified one promising candidate, Tl2Ba2CuO6+δ, that can be used to explore the superconductivity in the (seemingly) less complicated overdoped region of the cuprate phase diagram, using samples with minimal disorder.
We have grown high-quality single crystals of Tl2Ba2CuO6+δ with negligible orthorhombicity (<0.1%), and can be annealed reversibly across a very wide doping range (p = 0.05-0.29). This indicates that our samples are close to having perfect cation stoichiometry and no substitutional defects - solving a major issue which was faced by the previous efforts. This puts us in a position to map out the full phase diagram of clean cuprates, and thus take the crucial first step towards resolving the origin of their high Tc superconducting order.
Keywords: Cuprate Superconductors; Oxygen Annealing; X-ray Diffraction; SQUID Magnetometry; AC Nanocalorimetry