20 research outputs found
Microscopic annealing process and its impact on superconductivity in T'-structure electron-doped copper oxides
High-transition-temperature superconductivity arises in copper oxides when
holes or electrons are doped into the CuO2 planes of their insulating parent
compounds. While hole-doping quickly induces metallic behavior and
superconductivity in many cuprates, electron-doping alone is insufficient in
materials such as R2CuO4 (R is Nd, Pr, La, Ce, etc.), where it is necessary to
anneal an as-grown sample in a low-oxygen environment to remove a tiny amount
of oxygen in order to induce superconductivity. Here we show that the
microscopic process of oxygen reduction repairs Cu deficiencies in the as-grown
materials and creates oxygen vacancies in the stoichiometric CuO2 planes,
effectively reducing disorder and providing itinerant carriers for
superconductivity. The resolution of this long-standing materials issue
suggests that the fundamental mechanism for superconductivity is the same for
electron- and hole-doped copper oxides.Comment: 23 pages, 3 figures, accepted for publication in Nature Material