Condensed Matter Physics Seminar
| Date/Time: | Thursday, 06 Oct 2016 from 4:10 pm to 5:00 pm |
|---|---|
| Location: | Physics 18/19 |
| Phone: | 515-294-7377 |
| Channel: | College of Liberal Arts and Sciences |
| Actions: | Download iCal/vCal | Email Reminder |
Spatial and orbital distribution of doped holes in the cuprate high-temperature superconductors
Guichuan Yu, University of Minnesota
Using polarization-dependent X-ray absorption spectroscopy at the oxygen K-edge
and the copper L-edge, we have studied the symmetry and distribution of the
doping-induced states in the model cuprate superconductor HgBa2CuO4+? as a
function of the effective hole concentration p. At low doping levels, the holes
predominantly reside in the O 2px and 2py orbitals of the quintessential CuO2
planes. Their density increases linearly with doping and saturates at ps ? 0.10, well
below the optimal doping level (popt ? 0.15) where the superconducting transition
temperature takes on its maximum value of T c ? 97 K. For p > ps , additional doped
holes are found to enter the apical O 2pz orbitals. A complementary X-ray diffuse
scattering study of interstitial oxygen furthermore suggests that, for p > ps , some
holes remain in the Hg-O charge-reservoir layers instead of entering the CuO2
planes. Finally, we will show initial results of our work on electrostatically-doped
La 2 CuO(4+ ?) thin films that aims to understand the depth distribution of the doped
holes. This work was supported by DOE-BES.