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Electron phonon coupling and superconductivity in α-MoB₂ as a function of pressure

Carmona-Galván, M-A.; Heid, R. 1; De la Peña-Seaman, O.
1 Institut für QuantenMaterialien und Technologien (IQMT), Karlsruher Institut für Technologie (KIT)

Abstract (englisch):

We have studied the lattice dynamics, electron-phonon coupling, and superconducting properties of α-MoB2, as a function of applied pressure, within the framework of density functional perturbation theory using a mixed-basis pseudopotential method. We found that phonon modes located along the A−H, H−L, and L−A high-symmetry paths exhibit large phonon linewidths and contribute significantly to the electron-phonon coupling constant. Although linewidths are particularly large for the highest-frequency optical phonon modes (dominated by B vibrations), their contribution to the electron-phonon coupling constant is marginal. The latter is largely controlled by the acoustic low-frequency modes of predominantly Mo character. It was observed that at a pressure of 90 GPa, where α-MoB2 forms, the phonon-mediated pairing falls into the strong-coupling regime, and the estimate for the superconducting critical temperature Tc agrees well with experimental observations. When further increasing the applied pressure, a reduction of Tc is predicted, which correlates with a hardening of the acoustic low-frequency phonon modes and a decrease of the electron-phonon coupling parameter.


Postprint §
DOI: 10.5445/IR/1000164200
Frei zugänglich ab 28.10.2024
Zugehörige Institution(en) am KIT Institut für QuantenMaterialien und Technologien (IQMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 01.11.2023
Sprache Englisch
Identifikator ISSN: 0031-8949, 1402-4896
KITopen-ID: 1000164200
HGF-Programm 47.11.02 (POF IV, LK 01) Emergent Quantum Phenomena
Erschienen in Physica Scripta
Verlag Royal Swedish Academy of Sciences
Band 98
Heft 11
Seiten Art.-Nr.: 115975
Vorab online veröffentlicht am 27.10.2023
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