Electric field-induced quantum interference control in a semiconductor: A new manifestation of the Franz-Keldysh effect

TL;DR

This paper demonstrates how a constant electric field can enable quantum interference control of carrier injection in semiconductors through a nonlinear optical Franz-Keldysh effect, revealing a new way to manipulate electronic properties.

Contribution

It introduces a novel manifestation of the Franz-Keldysh effect enabling coherent control of carrier injection via electric fields in semiconductors.

Findings

Electric field allows coherent control of carrier injection.

Interference between one- and two-photon absorption induces ballistic current.

The mechanism applies to centrosymmetric semiconductors.

Abstract

In (100)-oriented GaAs illuminated at normal incidence by a laser and its second harmonic, interference between one- and two-photon absorption results in ballistic current injection, but not modulation of the overall carrier injection rate. Results from a pump-probe experiment on a transversely biased sample show that a constant electric field enables coherent control of the carrier injection rate. We ascribe this to the nonlinear optical Franz-Keldysh effect and calculate it for a two-band parabolic model. The mechanism is relevant to centrosymmetric semiconductors as well.