Theory of Thermal Relaxation of Electrons in Semiconductors

Sridhar Sadasivam, Maria K. Y. Chan, and Pierre Darancet
Phys. Rev. Lett. 119, 136602 – Published 27 September 2017
PDFHTMLExport Citation

Abstract

We compute the transient dynamics of phonons in contact with high energy “hot” charge carriers in 12 polar and nonpolar semiconductors, using a first-principles Boltzmann transport framework. For most materials, we find that the decay in electronic temperature departs significantly from a single-exponential model at times ranging from 1 to 15 ps after electronic excitation, a phenomenon concomitant with the appearance of nonthermal vibrational modes. We demonstrate that these effects result from slow thermalization within the phonon subsystem, caused by the large heterogeneity in the time scales of electron-phonon and phonon-phonon interactions in these materials. We propose a generalized two-temperature model accounting for phonon thermalization as a limiting step of electron-phonon thermalization, which captures the full thermal relaxation of hot electrons and holes in semiconductors. A direct consequence of our findings is that, for semiconductors, information about the spectral distribution of electron-phonon and phonon-phonon coupling can be extracted from the multiexponential behavior of the electronic temperature.

  • Figure
  • Figure
  • Figure
  • Received 13 May 2017

DOI:https://doi.org/10.1103/PhysRevLett.119.136602

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Sridhar Sadasivam*, Maria K. Y. Chan, and Pierre Darancet

  • Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA

  • *sadasivam@anl.gov
  • pdarancet@anl.gov

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 119, Iss. 13 — 29 September 2017

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×