Distribution of electrons and holes in cuprate superconductors as determined from O-17 and Cu-63 nuclear magnetic resonance

作者：Jurkutat Michael^*; Rybicki Damian; Sushkov Oleg P; Williams Grant V M; Erb Andreas; Haase Juergen

来源：Physical Review B, 2014, 90(14): 140504.

DOI：10.1103/PhysRevB.90.140504

The local distribution of electrons and holes in the CuO2 plane of the high-temperature superconducting cuprates is determined with nuclear magnetic resonance through the quadrupole splittings of O-17 and Cu-63. Based on new data for single crystals of electron-doped Pr2-x Ce-x CuO4 (x = 0, 0.05, 0.10, 0.15) as well as Nd2-x Ce-x CuO4 (x = 0, 0.13) the changes in hole contents n(d) of Cu 3d(x2-y2) and n(p) of O 2p(sigma) orbitals are determined and these account for the stoichiometrically doped charges, similar to hole-doped La2-x Sr-x CuO4. It emerges that while n(d) + 2n(p) = 1 in all parent materials as expected, n(d) and n(p) vary substantially between different groups of materials. Doping holes increases predominantly n(p), but also n(d). To the contrary, doping electrons predominantly decreases nd and only slightly n(p). However, n(p) for the electron-doped systems is higher than that in hole-doped La1.85Sr0.15CuO4. Cuprates with the highest maximum T-c%26apos;s appear to have a comparatively low nd and high np. The rather high oxygen hole content of the Pr2CuO4 and Nd2CuO4 with the low nd seems to make them ideal candidates for hole doping to obtain a potentially high T-c.

• 出版日期2014-10-20