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Exciton control in a room temperature bulk semiconductor with coherent strain pulses.

ABSTRACT: Controlling the excitonic optical properties of room temperature semiconductors using time-dependent perturbations is key to future optoelectronic applications. The optical Stark effect in bulk and low-dimensional materials has recently shown exciton shifts below 20 meV. Here, we demonstrate dynamical tuning of the exciton properties by photoinduced coherent acoustic phonons in the cheap and abundant wide-gap semiconductor anatase titanium dioxide (TiO2) in single crystalline form. The giant coupling between the excitons and the photoinduced strain pulses yields a room temperature exciton shift of 30 to 50 meV and a marked modulation of its oscillator strength. An advanced ab initio treatment of the exciton-phonon interaction fully accounts for these results, and shows that the deformation potential coupling underlies the generation and detection of the giant acoustic phonon modulations.

SUBMITTER: Baldini E

PROVIDER: S-EPMC6884413 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Exciton control in a room temperature bulk semiconductor with coherent strain pulses.

Baldini Edoardo E Dominguez Adriel A Palmieri Tania T Cannelli Oliviero O Rubio Angel A Ruello Pascal P Chergui Majed M

Science advances 20191129 11

Controlling the excitonic optical properties of room temperature semiconductors using time-dependent perturbations is key to future optoelectronic applications. The optical Stark effect in bulk and low-dimensional materials has recently shown exciton shifts below 20 meV. Here, we demonstrate dynamical tuning of the exciton properties by photoinduced coherent acoustic phonons in the cheap and abundant wide-gap semiconductor anatase titanium dioxide (TiO<sub>2</sub>) in single crystalline form. Th ...[more]

PMID: 31819899

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