Design of structured La${}_{2-x}$Sr${}_x$CuO${}_4$ films as superconducting transition-edge sensors at 4.2K

We calculate the effects of carrier-density structuration and patterning on thin films of the cuprate superconductor La${}_{2-x}$Sr${}_x$CuO${}_4$, in order to optimize its functional characteristics as sensing material for resistive transition-edge bolometers at liquid-He temperature. We perform finite-element computations considering two major contributions to structuration: The intrinsic random nanoscale disorder associated to carrier density nonstoichiometry, plus the imposition of regular arrangements of zones with different nominal carrier densities. Using ad-hoc seek algorithms, we obtain various structuration designs that markedly improve the bolometric performance, mainly the saturation power and dynamic range. Bolometric operation becomes favorable even in the easier-to-implement constant current mode of measurement.