European Physical Journal B, Condensed Matter Physics vol:29 issue:3 pages:369-375
We have studied the temperature dependent resistivity rho(T) of La2-xSrxCuO4 epitaxial thin films in the doping range 0.045 less than or equal to x less than or equal to 0.25 in pulsed magnetic fields up to 50 T. The zero-field resistivity rho(T) of these samples in the pseudogap, regime, can be scaled onto one single universal curve in a broad temperature range by using a linear transformation of both temperature and resistivity. The high field data rho(T) reveal a metal to insulator transition (MIT) at low temperatures, well into the overdoped regime. For samples having k(F)l < 1, with k(F) the Fermi wave vector and l the mean free path, this low temperature insulating behavior of the resistivity is described by the variable range hopping conductivity (VRH). For samples with k(F)l > 1, the divergence follows rho(T) similar to In(1/T) or a power law, depending upon the Sr-content. We further found that the residual conductivity at the minimum in rho(T), appearing due to the MIT, follows a linear behavior with respect to the Sr-content. It is argued that the unusual MIT in compounds with k(F)l > 1, is most probably associated with the pseudogap and the behavior of charge stripes at low temperatures.