Thickness-driven shift of the superconducting dome in the phase diagram of epitaxial cuprate thin films

The thickness-driven disorder effect has long been subject of interest in thin-film superconductors, given the direct relation between the superconductivity and film thickness. In La2−xSrxCuO4 thin films, disorder is known to suppress superconductivity and hinder charge transport. However, most previous studies have focused on the optimally doped regime, while the underdoped and overdoped regions remain less explored. In this study, we report a shift of the superconducting dome in the phase diagram of La2−xSrxCuO4 thin films toward the overdoped regime, driven by thickness-induced disorder. Sheet resistance vs temperature curves measured at various Sr doping levels reveal electronic transport characteristics consistent with underdoped behavior, further supporting the role of disorder. The origin of this disorder effect is cautiously attributed to oxygen vacancies, which reduce the effective hole carrier density. Overall, our result confirms the shift of the superconducting dome and highlights the critical influence of film thickness and disorder in La2−xSrxCuO4 thin films.