Abstract
We use a local model to study the formation and the structure of the low-energy charge-transfer excitations in the insulating ${\mathrm{C}\mathrm{u}\ensuremath{-}\mathrm{O}}_{2}$ plane. The elementary excitation is a bound exciton of spin singlet, consisting of a ${\mathrm{Cu}}^{+}$ and a neighboring spin singlet of Cu-O holes. The exciton can move through the lattice freely without disturbing the antiferromagnetic spin background, in contrast to the single hole motion. There are four eigenmodes of excitons with different symmetry. The $p$-wave-like exciton has a large dispersion width. The $s$-wave-like exciton mixes with the $p$ state at finite momentum, and its dipole transition intensity is strongly anisotropic. The model is in excellent agreement with the electron energy-loss spectra in the insulating ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{2}{\mathrm{Cl}}_{2}.$
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.