Electronic screening-enhanced hole pairing in two-leg spin ladders studied by high-resolution resonant inelastic x-ray scattering at Cu M edges

A Rusydi; A Goos; S Binder; A Eich; K Botril; P Abbamonte; X Yu; M B H Breese; H Eisaki; Y Fujimaki; S Uchida; N Guerassimova; R Treusch; J Feldhaus; R Reininger; M V Klein; M Rübhausen

doi:10.1103/PhysRevLett.113.067001

Electronic screening-enhanced hole pairing in two-leg spin ladders studied by high-resolution resonant inelastic x-ray scattering at Cu M edges

Phys Rev Lett. 2014 Aug 8;113(6):067001. doi: 10.1103/PhysRevLett.113.067001. Epub 2014 Aug 4.

Authors

A Rusydi¹, A Goos², S Binder², A Eich², K Botril², P Abbamonte³, X Yu⁴, M B H Breese⁵, H Eisaki⁶, Y Fujimaki⁷, S Uchida⁷, N Guerassimova⁸, R Treusch⁸, J Feldhaus⁸, R Reininger⁹, M V Klein³, M Rübhausen¹⁰

Affiliations

¹ Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany and NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
² Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany.
³ Physics Department and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA.
⁴ Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
⁵ NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
⁶ Nanoelectronics Research Institute, AIST, 1-1-1 Central 2, Umezono, Tsukuba, Ibaraki 305-8568, Japan.
⁷ Department of Superconductivity, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan.
⁸ Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany.
⁹ Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
¹⁰ Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany and NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore.

PMID: 25148343
DOI: 10.1103/PhysRevLett.113.067001

Abstract

We study the electronic screening mechanisms of the effective Coulomb on-site repulsion in hole-doped Sr(14)Cu(24)O(41) compared to undoped La(6)Ca(8)Cu(24)O(41) using polarization dependent high-resolution resonant inelastic x-ray scattering at Cu M edges. By measuring the energy of the effective Coulomb on-site repulsion and the spin excitations, we estimate superexchange and hopping matrix element energies along rungs and legs, respectively. Interestingly, hole doping locally screens the Coulomb on-site repulsion reducing it by as much as 25%. We suggest that the increased ratio of the electronic kinetic to the electronic correlation energy contributes to the local superexchange mediated pairing between holes.