Programme

O.2 -- Oral, VCTP-50

Date: Monday, 4 August 2025

Time: 11:35 - 12:00

Structure Prediction in the Search for Hydride-Based High-Temperature Superconductors

Duc-Long Nguyen[1], Viet-Ha Chu[2], Truong-Tho Pham[1]

[1] Simulation in Materials Science Research Group, Science and Technology Advanced Institute, Van Lang University, Ho Chi Minh City, Vietnam [2] Department of Physics, TNU-University of Education, Thai Nguyen, Vietnam

Materials scientists have long chased the dream of finding a superconductor that works at room temperature, and this ambition continues to fuel ceaseless experimentation. In the present study, computer-aided crystal-structure prediction identified a novel hydride, YSc2H24, that crystallizes in a hexagonal lattice with space group P6/mmm and survives only under extremely high pressures. Its arrangement is striking: dual metallic cages, one housing Sc and the other containing Y, nest within the lattice like Russian dolls, lending the material unusual geometric properties. A comprehensive calculation, which projected phonon dispersions, mapped electron-phonon coupling, and solved the isotropic Eliashberg equation, yielded an exceptionally high dimensionless coupling constant, λ = 3.27, and pinned the critical temperature Tc between 302 and 330 K at roughly 310 GPa. Remarkably, Tc remains above room temperature even as the external pressure increases. Should experimental verification follow, the compound's exceptional Tc and cage-like topology promise fresh insights into the already puzzling physics of high-temperature superconductivity and may open doors to entirely new classes of applications. [1] Pham, Truong-Tho, Viet-Ha Chu, and Duc-Long Nguyen. "First principles prediction unveils high-T c superconductivity in YSc 2 H 24 cage structures under pressure." Journal of Materials Chemistry C 12.42 (2024): 17254-17262. [2] Pham, Truong-Tho, and Duc-Long Nguyen. "First-principles prediction of superconductivity in MgB 3 C 3." Physical Review B 107.13 (2023): 134502.

Presenter: Nguyen Duc-Long