Ultrafast Hot Phonon Dynamics in MgB2 Driven by Anisotropic Electron-Phonon Coupling

The zone-center E2g modes play a crucial role in MgB2, controlling the scattering mechanisms in the normal state as well the superconducting pairing. Here, we demonstrate via first-principles quantum-field theory calculations that, due to the anisotropic electron-phonon interaction, a hot-phonon reg...

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Bibliographic Details
Published in:	Physical review letters Vol. 124; no. 7; p. 1
Main Authors:	Novko, Dino, Caruso, Fabio, Draxl, Claudia, Cappelluti, Emmanuele
Format:	Journal Article
Language:	English
Published:	College Park American Physical Society 21-02-2020
Subjects:	Electron phonon interactions Field theory First principles Magnesium compounds Phonons Raman spectroscopy Spectral signatures
Online Access:	Get full text
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Summary:	The zone-center E2g modes play a crucial role in MgB2, controlling the scattering mechanisms in the normal state as well the superconducting pairing. Here, we demonstrate via first-principles quantum-field theory calculations that, due to the anisotropic electron-phonon interaction, a hot-phonon regime where the E2g phonons can achieve significantly larger effective populations than other modes, is triggered in MgB2 by the interaction with an ultrashort laser pulse. Spectral signatures of this scenario in ultrafast pump-probe Raman spectroscopy are discussed in detail, revealing also a fundamental role of nonadiabatic processes in the optical features of the E2g mode.
ISSN:	0031-9007 1079-7114
DOI:	10.1103/PhysRevLett.124.077001