# Peculiarities in the concentration dependence of the superconducting transition temperature in the bipolaron theory of Cooper pairs

## TL;DR

This paper explores how the bipolaron theory predicts a non-monotonic dependence of the superconducting transition temperature on doping levels, potentially explaining the universal 1/8 anomaly in superconductors.

## Contribution

It introduces a novel perspective on doping dependence in superconductivity based on bipolaron theory, highlighting the possibility of superconducting phases at both low and high doping levels.

## Key findings

- Superconducting phase may exist at low and high doping, but not at intermediate levels.
- The 1/8 anomaly could have a universal origin related to bipolaron behavior.
- Doping dependence of Tc shows peculiar concentration dependence in bipolaron theory.

## Abstract

It is shown that the bipolaron theory of Cooper pairs suggests that there is a possibility for a superconducting phase to exist at low and high levels of doping and be absent at intermediate level of doping. The results obtained imply possibly universal character of 1/8 anomaly.