# Prospects to attain room temperature superconductivity

## TL;DR

This paper derives simple formulas to estimate superconducting transition temperatures, suggesting room temperature superconductivity requires very high Debye temperatures and identifying potential materials like a Be-Pb alloy that could superconduct at 44 K.

## Contribution

It introduces new analytical expressions for estimating Tc and gap ratios, highlighting the limits of phonon-mediated superconductivity and potential candidate materials.

## Key findings

- Maximum phonon exchange factor is 2.67
- Room temperature superconductivity requires Debye temperature ~1800 K
- Be-Pb alloy could superconduct at around 44 K

## Abstract

With a generic model for the electron-phonon spectral density, two simple expressions are derived to estimate the transition temperature and gap-to-temperature ratio in conventional superconductors. They entail that on average the numerical value of the phonon exchange factor, $\lambda$, is limited to 2.67, so that room temperature superconductivity may be attained only with a Debye temperature of about 1800 K or higher, in materials that may or may not involve hydrogen. They also show that a Be-Pb alloy may become a superconductor at $\sim$44 K.