Searching for ambient-pressure conventional superconductors with critical temperatures (TC) higher than 40 K is a key challenge in the field of high-temperature superconductivity, mainly due to lack of efficient and effective models for rapidly screening candidate systems. In this work, we propose a simplified model that separates the dimensionless electron-phonon coupling (EPC) strength \(\lambda\) into two components: while the EPC matrix elements evaluating the pairing strength are computationally expensive to obtain, the phonon-assisted nesting function \(P\left(\omega \right)\), which evaluates the matching of electron bands and phonon spectra for forming potential electron pairs via phonons, can be easily and accurately calculated. Our model illuminates the critical role of \(P\left(\omega \right)\) and its spectral integral \(P\) in determining \(\lambda\), i.e., high \(P\) is a necessary condition leading to large \(\lambda\) and thus high TC, which is further demonstrated by showing that the reported high-TC traditional superconductors in literatures all have high \(P\). As an easily quantifiable parameter, \(P\left(\omega \right)\) and \(P\) provide an efficient and effective descriptor for accelerating the discovery and rational design of high-TC superconductors. By applying the model to screen over the Computational 2D Materials Database (C2DB), we successfully identify several high-TC superconducting systems as confirmed by accurate first-principles calculations. Our model opens new avenues for exploring high-TC systems.
