The enigmatic scaling behaviour of the normal state properties of the high Tc cuprates has been explained by assuming that a crossover from the two- dimensional Heisenberg (2D-H) to the one-dimensional spin ladder (1D-SL) regime takes place at temperature T=T*. For T<T* stripe formation results in the quantum 1D transport with the characteristic inelastic length L_phi being fully controlled by the magnetic correlation length xi_m of the even-chain SL, whereas for T> T* the 2D quantum transport is realized with L_\phi governed by the 2D-H correlations L_phi=xi_m=exp(J/T)$. Therefore, the pseudogap found in underdoped (p<p_opt) high Tc's is the spin-gap Delta(p) in even-chain 1D-SL.
Categories: cond-mat.supr-con cond-mat.str-el