Hole localization in strongly correlated and disordered systems; DMRG studies for 1-D and 3-leg ladder random Hubbard models

Okumura, Masahiko   ; Yamada, Susumu  ; Taniguchi, Nobuhiko*; Machida, Masahiko  

We study one-dimensional and 3-leg ladder repulsive Hubbard models with random potential by using the density-matrix renormalization group method. When holes are slightly doped to the half-filling, the local Mott phase called "Mott plateau" and the local dip structure in density profile called "hole localized valley" are well-separately observable in strong on-site repulsive U=t and strong randomness for both models. We suggest that these separated structures qualitatively capture locally inhomogeneous characters seen in heavily under-doped High-Tc superconductors.