Zhang Jianbo, Ding Yang, Chen Cheng-Chien, Cai Zhonghou, Chang Jun, Chen Bijuan, Hong Xinguo, Fluerasu Andrei, Zhang Yugang, Ku Ching-Shun, Brewe Dale, Heald Steve, Ishii Hirofumi, Hiraoka Nozomu, Tsuei Ku-Ding, Liu Wenjun, Zhang Zhan, Cai Yong Q, Gu Genda, Irifune Tetsuo, Mao Ho-Kwang
Center for High-Pressure Science & Technology Advanced Research , Beijing , 100094 , People's Republic of China.
Department of Physics , University of Alabama at Birmingham , Birmingham , Alabama 35294 , United States.
J Phys Chem Lett. 2018 Aug 2;9(15):4182-4188. doi: 10.1021/acs.jpclett.8b01849. Epub 2018 Jul 13.
One challenge in studying high-temperature superconductivity (HTSC) stems from a lack of direct experimental evidence linking lattice inhomogeneity and superconductivity. Here, we apply synchrotron hard X-ray nanoimaging and small-angle scattering to reveal a novel micron-scaled ribbon phase in optimally doped BiSrCaCuO (Bi-2212, with δ = 0.1). The morphology of the ribbon-like phase evolves simultaneously with the dome-shaped T behavior under pressure. X-ray absorption studies show that the increasing of T is associated with oxygen-hole redistribution in the CuO plan, while T starts to decrease with pressure when oxygen holes become immobile. Additional X-ray irradiation experiments reveal that nanoscaled short-range ordering of oxygen vacancies could further lower T, which indicates that the optimal T is affected not only by an optimal morphology of the ribbon phase, but also an optimal distribution of oxygen vacancies. Our studies thereby provide for the first time compelling experimental evidence correlating the T with micron to nanoscale inhomogeneity.
