The distribution of holes in Sr14-x Cax Cu24 O41 is revisited with semiempirical reanalysis of the x-ray absorption data and exact diagonalization cluster calculations. Another interpretation of the XAS data leads to much larger ladder hole densities than previously suggested. These new hole densities lead to a simple interpretation of the hole Wigner crystal recently reported with 1 3 and 1 5 wave vectors along the ladder. Our interpretation is consistent with paired holes in the rung of the ladders. Exact diagonalization results for a minimal model of the doped ladders suggest that the stabilization of spin structures consisting of 4 spins in a square plaquette as a result of resonance valence bond physics suppresses the hole crystal with a 1 4 wave vector.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Mar 21 2007|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics