SciPost Physics

SciPost Phys. 12, 173 (2022) · published 24 May 2022

• doi: 10.21468/SciPostPhys.12.5.173
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Abstract

The time dynamics of the energy flow from electronic to lattice degrees of freedom in pump-probe setups could be strongly affected by the presence of a hot-phonon bottleneck, which can sustain longer coherence of the optically excited electronic states. Recently, hot-phonon physics has been experimentally observed and theoretically described in MgB$_2$, the electron-phonon based superconductor with $T_{\rm c}\approx 39$ K. By employing a combined ab-initio and quantum-field-theory approach and by taking MgB$_2$ as an example, here we propose a novel path for revealing the presence and characterizing the properties of hot phonons through a direct analysis of the information encoded in the lattice inter-atomic correlations. Such method exploits the underlying symmetry of the $E_{2g}$ hot modes characterized by a out-of-phase in-plane motion of the two boron atoms. Since hot phonons occur typically at high-symmetry points of the Brillouin zone, with specific symmetries of the lattice displacements, the present analysis is quite general and it could aid in revealing the hot-phonon physics in other promising materials, such as graphene, boron nitride, or black phosphorus.

• Inayoshi et al., Energy Flow during Relaxation in an Electron–Phonon System with Multiple Modes: A Nonequilibrium Green’s Function Study
  J. Phys. Soc. Jpn. 92, 124001 (2023) [Crossref]
• Yu et al., Superconductive materials with MgB2 -like structures from data-driven screening
  Phys. Rev. B 105, 214517 (2022) [Crossref]
• Cappelluti et al., Properties and challenges of hot-phonon physics in metals: MgB2 and other compounds
  Progress in Surface Science 97, 100664 100664 (2022) [Crossref]