An echo of the low-temperature phase competition and 1/8 dip in room-temperature properties of cuprate HTSCs

Abstract

Cuprate high-temperature superconductors (HTSCs) exhibit a characteristic dome-shaped dependence of the superconducting transition temperature on the charge carrier concentration Tc(p) featuring a maximum at optimal doping p = 0.16. Near the p ~ 1/8 composition, a sharp suppression of Tc occurs (the so-called "1/8 anomaly"), which is conventionally attributed to charge and spin ordering in the CuO2 planes. By investigating the hydration process of La2-xBaxCuO4 and YBa2Cu3O6+delta conducted at room temperature (RT) under the influence of a high-frequency magnetic field, we report anomalous weight changes in the HTSC samples during the initial stage of hydration. For both compounds, the p-concentration dependence of these weight changes closely mirrors the respective Tc(p) profiles, including the signature "1/8 anomaly". Such a prominent manifestation of characteristic low-temperature features of HTSC systems at RT provides critical insights into the stability of low-temperature electronic correlations. These experimental findings offer new prerequisites for the ongoing development of theoretical models of HTSC.