Predicted superconductivity above 100 K in electride Li4Rh under high pressure

Although numerous high-pressure electride (HPE) superconductors have been reported, their superconducting transition temperatures (Tc) are low. No HPE superconductor with a Tc exceeding 100 K has been reported. Herein, we predicted a HPE superconductor, Li4Rh, with a high Tc=108.2 K at 300 GPa, making it the first HPE superconductor with a Tc exceeding 100 K. Li4Rh features strong hybridization between nonnuclear attractors (NNAs) and atoms near the Fermi level and a large, deformed cylindrical Fermi sheet. This Fermi sheet structure induces strong electron-phonon coupling (EPC) and allows a broad range of electrons and phonons with a wide range of q vectors to participate in EPC, resulting in high Tc. Unlike other HPE superconductors, the Tc of Li4Rh does not decrease with decreasing EPC but remains stable because the logarithmic average phonon frequency increases as the EPC strength decreases. This helps maintain Tc with increasing pressure with little fluctuation. The results indicate that HPEs with strong hybridization between NNAs and atoms near the Fermi level and with large and closed Fermi surfaces are more likely to exhibit high Tc, offering deep insights into HPE superconductivity and providing valuable guidance for future research into high-Tc electrides.