Designing Superconductors with Supercomputers
Dr. Christoph Heil
Institute of Theoretical and Computational Physics, Graz University of Technology
16:15 - 17:15 Tuesday 14 November 2023 TUG Designing materials with advanced functionalities is the main focus of contemporary solid-state physics and chemistry. In this talk, I will explore the in-silico prediction of superconducting materials from first principles, combining cutting-edge methods in crystal structure prediction, stability determination, and the efficient and accurate calculation of electron-phonon interactions.
I will illustrate these principles using recent work from our research, wherein we predict a new ternary hydride, LaBH8, which is the first example of a conventional superconductor with a Tc = 126 K, i.e. exceeding the boiling point of N2 (77 K), that should remain dynamically stable down to 35 GPa [1]. Using the XYH8 template as a starting point, we further identify two silicides that are an improvement to LaBH8: SrSiH8 with a dynamical stability pressure pc of 27 GPa and a Tc of 127 K, and even more remarkably, BaSiH8 that is dynamically stable down to pressures of 3 GPa with a critical temperature of 71 K [2]. In addition, we introduce the more rigorous concept of kinetic stability in order to judge the synthesizability of a material [2,3]. Investigating another hydride template, namely, XYH6, we predict high-Tc superconductivity at ambient pressures and propose a feasible synthesis route [4].
I will also touch upon the controversal announcement of room-temperature superconductivity at near-ambient pressures in Lu-N-H [5] and discuss why this is not possible within the framework of electron-phonon coupling superconductivity [6,7].
[1] S. Di Cataldo et al., PRB 104, L020511 (2021)
[2] R. Lucrezi et al., npj Comp. Mat. 8, 119 (2022)
[3] R. Lucrezi et al., Commun. Phys. 6, 298 (2023)
[4] K. Dolui et al., arXiv:2310.07562
[5] N. Dasenbrock-Gammon et al., Nature 615, 244 (2023)
[6] P. Ferreira et al., Nat. Commun. 14, 5367 (2023)
[7] R. Lucrezi et al., arXiv:2304.06685
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