English

Spin-1 chain doped with mobile S=1/2 fermions

Condensed Matter 2009-10-31 v1

Abstract

We investigate doping of a two-orbital chain with mobile S=1/2S=1/2 fermions as a valid model for Y2xCaxBaNiO5\rm Y_{2-x}Ca_xBaNiO_5. The S=1 spins are stabilized by strong, ferromagnetic (fm) Hund's rule couplings. We calculate correlation functions and thermodynamic quantities by DMRG methods and find a new hierarchy of energy scales in the spin sector upon doping. Gapless spin-excitations are generated at a lower energy scale by interactions among itinerant polarons created by each hole and coexist with the larger scale of the gapful spin-liquid background of the S=1 chain accompanied by a finite string-order parameter.

Keywords

Cite

@article{arxiv.cond-mat/9912273,
  title  = {Spin-1 chain doped with mobile S=1/2 fermions},
  author = {Beat Ammon and Masatoshi Imada},
  journal= {arXiv preprint arXiv:cond-mat/9912273},
  year   = {2009}
}

Comments

5 pages and 5 eps-figures