The temperature dependence of the nonlinear current-voltage (I-V) characteristics in highly underdoped La2−xSrxCuO4 (x=0.07 and 0.08) thick films has been studied in both zero and perpendicular magnetic fields H. Power-law behavior of V(I) is found for both H=0 and H=0. The critical current Ic was extracted, and its temperature and magnetic field dependences were studied in detail. The Berezinskii-Kosterlitz-Thouless physics dominates the nonlinear I-V near the superconducting transition at H=0, and it continues to contribute up to a characteristic temperature Tx(H). Nonlinear I-V persists up to an even higher temperature Th(H) due to the depinning of vortices.
@article{arxiv.1609.01644,
title = {Current-voltage characteristics and vortex dynamics in highly underdoped La$_{2-x}$Sr$_{x}$CuO$_{4}$},
author = {Zhenzhong Shi and P. G. Baity and Dragana Popović},
journal= {arXiv preprint arXiv:1609.01644},
year = {2016}
}