Terahertz electron-hole recollisions in GaAs/AlGaAs quantum wells: robustness to scattering by optical phonons and thermal fluctuations

TL;DR

This study demonstrates that electron-hole recollisions in GaAs/AlGaAs quantum wells produce high-order sidebands resilient to LO phonon scattering and thermal effects, even at room temperature, revealing robustness of quantum recollision phenomena.

Contribution

It shows that high-order electron-hole recollision sidebands persist despite LO phonon scattering and thermal fluctuations, extending understanding of quantum recollision robustness.

Findings

Up to 18 sidebands observed at 12 K

Sidebands with order up to 22 persist at room temperature

LO phonon scattering suppresses but does not eliminate high-energy sidebands

Abstract

Electron-hole recollisions are induced by resonantly injecting excitons with a near-IR laser at frequency $f_{\text{NIR}}$ into quantum wells driven by a ~10 kV/cm field oscillating at $f_{\text{THz}} = 0.57$ THz. At $T=12$ K, up to 18 sidebands are observed at frequencies $f_{\text{sideband}}=f_{\text{NIR}}+2n f_{\text{THz}}$, with $-8 \le 2n \le 28$. Electrons and holes recollide with total kinetic energies up to 57 meV, well above the $E_{\text{LO}} = 36$ meV threshold for longitudinal optical (LO) phonon emission. Sidebands with order up to $2n=22$ persist up to room temperature. A simple model shows that LO phonon scattering suppresses but does not eliminate sidebands associated with kinetic energies above $E_{\text{LO}}$.