Possible evidence of charge-stripe ordering in the ab-plane resistivity ofstrongly underdoped La2-xSrxCuO4 single crystals

We measured the ab-plane resistivity of La2-xSrxCuO4 underdoped single crys tals (x=0.052 and x=0.06) between 4.2 and 300 K by using an AC version of t he Van der Pauw technique. We suggest that a possible scenario of charge-st ripe ordering at the lowering of the temperature can be delineated by start ing from the main. features of the rho (ab)(T) curves of these samples. In particular, the deviation from the linearity of the ab-plane resistivity, o ccurring at a temperature T-ch, could be related to the beginning of the ch arge localization, and the upturn of rho (ab) to the progressive pinning of the resulting charge stripes. By starting from an analysis of our ab-plane resistivity curves, we determined the temperature of charge ordering T-ch for our samples, thus extending in consistent way the T-ch vs. x curve repo rted in literature to the very low-doping region of the phase diagram.