CMSP Seminar: Search for new electride high temperature superconductors
Starts 31 May 2023 11:00
Ends 31 May 2023 12:00
Central European Time
Luigi Stasi Seminar Room + Zoom
Edison Z. da Silva
Institute of Physics Gleb Wataghin
University of Campinas-UNICAMP-SP-Brazil
The search for superconductivity in new materials have been intense and in this century a new class of materials have been shown to present superconductivity. Under pressure, many new electride superconductors have been discovered or proposed. The present work discusses two new materials proposed as new high temperature superconductors, one under pressure, Li5C and the other Mo2N at ambient pressure.
Using density functional theory (DFT) in association with particle swarm search method (PSO), we discovered a remarkable electride superconductor, Li5C. This new predicted material is stable for pressures from 50 to 210 GPa. It is also shown that Li5C has a significant electron-phonon coupling and estimated superconducting critical temperature Tc = 48.3 K at pressure 210 GPa, the highest Tc already reported for lithium-carbon compounds and one of the highest known Tc for electrides under pressure.
We also discuss superconductivity in the 2-D electrene Mo2N. Using DFT associated with Migdal-Eliasberg approach and maximally localized Wannier functions, this study shows how biaxial strain affects superconductivity in a monolayer of Mo2N. Results indicate that 2-D Mo2N presents strong electron-phonon coupling with large anisotropy in the superconducting energy gap.
A single layer of Mo2N is an electride with localized electron gas pockets on the surface, resembling anions adsorbed on an atomic sheet. At low temperatures, this material shows superconductivity and calculations point to Tc = 24.7 K, a record high transition temperature for this class of material at ambient pressure.
Predicted Superconductivity in Electride Li5C.
Zenner S. Pereira, Giovani M. Faccin, and E. Z. da Silva. JPC-C -125 (16), 8899-8906 (2021) https://doi.org/10.1021/acs.jpcc.1c02329 Strain-induced Multigap Superconductivity in Electrene Mo2N: A First Principles Study.
Zenner S. Pereira, Giovani M. Faccin, and E. Z. da Silva. NANOSCALE, 14, 24, 8549-8600 (2022) https://doi.org/10.1039/D2NR00395C