Lattice dynamics in the FeSi-based family of superconductors

Samar Layek; Mads Fonager Hansen; Jean-Baptiste Vaney; Pierre Toulemonde; Sophie Tencé; Philippe Boullay; Andres Cano; Marie-Aude Méasson

arXiv · 2307.12610

Lattice dynamics in the FeSi-based family of superconductors

Samar Layek·Mads Fonager Hansen·Jean-Baptiste Vaney·Pierre Toulemonde·Sophie Tencé·Philippe Boullay·Andres Cano·Marie-Aude Méasson

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Abstract

The lattice dynamics of the superconducting materials LaFeSiH and LaFeSiO as well as their intermetallic precursor LaFeSi are investigated by polarized Raman spectroscopy and first-principles calculations, together with X-ray and advanced electron diffraction techniques for their structural analysis. We find that the Fe-dominated Raman-active modes reflect the chemical peculiarities of these silicides compared to their pnictide counterparts, with enhanced structural couplings between the FeSi layer and the spacer that can be related to the ionic vs covalent character of the latter. In addition, we find signatures of enhanced electron-phonon coupling for some of the Raman-active modes. Beyond that, our study reveals intriguing Fe-based Raman features as well as structural subtleties in LaFeSiH suggesting that this superconductor may formally be non-centrosymmetric.

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Samar Layek, Mads Fonager Hansen, Jean-Baptiste Vaney, Pierre Toulemonde, Sophie Tencé, Philippe Boullay, Andres Cano, Marie-Aude Méasson. 2023-07-24. Lattice dynamics in the FeSi-based family of superconductors. https://arxiv.org/abs/2307.12610

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