engleski

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 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.

electron-phonon coupling, ultrafast dynamics, high-Tc superconductors, DFT

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