Nonlinear Doping of Cuprate Superconductors -- The case of Bi_2Sr_{2-x}La_xCuO_{6+\delta}

TL;DR

This paper investigates the nonlinear hole doping mechanism in Bi_2Sr_{2-x}La_xCuO_{6+\delta} and identifies a feedback process that stabilizes optimal doping levels around n_opt=0.16, crucial for high-temperature superconductivity.

Contribution

It reveals a nonlinear doping mechanism involving feedback between CuO_2 layers and dopant reactants, explaining the optimal doping in Bi-based cuprates.

Findings

Optimal doping occurs at x=0.35 with n_opt=0.16

Feedback mechanism stabilizes hole concentration

Doping process is nonlinear and self-regulating

Abstract

We analyze the hole doping mechanism in Bi_2Sr_{2-x}La_xCuO_{6+\delta} (BSLCO). The singular optimum around x=0.35 is found to be connected with a feedback between the doped CuO_2 layers and its dopant reactant [La^{3+}/Bi^{3+}-O_\delta] locking the number of doped holes preferentially on to the universal optimum n_opt=0.16.