2. The existence of charge-stripe ordering in the underdoped regime of cuprates (charge stripes in HTSC) has long been one of the most intriguing subjects of debate concerning HTSC. Based on some theoretical and experimental papers, we used an AC van der Pauw technique to measure the ab-plane resistivity of strongly underdoped La_2-xSr_xCuO₄ single crystals as a function of the temperature, with the aim of studying the effect of charge-stripe ordering in the r_ab(T) curve. By exploiting some previous results that established a relationship between the stripe ordering temperature T_ch measured by NQR (nuclear quadrupole resonance) and the temperature dependence of the resistivity, we were able to extend the T_ch (x) curve to the extreme underdoped region. The results were found to be in good agreement with those obtained at higher doping values.

R.S. Gonnelli, V.A. Stepanov, A. Morello, G.A. Ummarino, Francesca Licci, G. Ubertalli
“ab-plane resistivity and possible charge stripe ordering in strongly underdoped La_2-xSr_xCuO₄ single crystals”, Physica C 341-348, 1779 (2000).