Researchers gain deeper understanding of mechanism behind superconductors

Phys.org  January 17, 2023
High-temperature superconducting cuprates respond to doping with a dome-like dependence of their critical temperature (Tc). But the family-specific maximum Tc can be surpassed by application of pressure. Researchers in Germany investigated the phenomenon with high-pressure anvil cell NMR and measured the charge content at planar Cu and O, and with it the doping of the CuO2. They found that pressure increases the overall hole doping but when it enhances Tc above what can be achieved by doping, pressure leads to a hole redistribution favoring planar O. This is similar to the observation that the family-specific maximum Tc is higher for materials where the hole content at planar O is higher at the expense of that at planar Cu. It reflects dependence of the maximum Tc on the Cu–O bond covalence and the charge-transfer gap…read more. Open Access TECHNICAL ARTICLE 

Anvil cell high-pressure exerted on YBa2Cu3O6 + y changes the charges in the CuO2 plane… Credit: PNAS, January 6, 2023, 120 (2) e2215458120