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arXiv · 1903.08553

Ultrafast band-gap renormalization and build-up of optical gain in monolayer MoTe$_2$

Lars Meckbach·Jörg Hader·Josefine Neuhaus·Ulrich Huttner·Johannes Steiner·Tineke Stroucken·Jerry V. Moloney·Stephan W. Koch
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Abstract

The dynamics of band-gap renormalization and gain build-up in monolayer MoTe$_2$ is investigated by evaluating the non-equilibrium Dirac-Bloch equations with the incoherent carrier-carrier and carrier-phonon scattering treated via quantum-Boltzmann type scattering equations. For the case where an approximately $300$ fs-long high intensity optical pulse generates charge-carrier densities in the gain regime, the strong Coulomb coupling leads to a relaxation of excited carriers on a few fs time scale. The pump-pulse generation of excited carriers induces a large band-gap renormalization during the time scale of the pulse. Efficient phonon coupling leads to a subsequent carrier thermalization within a few ps, which defines the time scale for the optical gain build-up energetically close to the low-density exciton resonance.

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Lars Meckbach, Jörg Hader, Josefine Neuhaus, Ulrich Huttner, Johannes Steiner, Tineke Stroucken, Jerry V. Moloney, Stephan W. Koch. 2019-03-20. Ultrafast band-gap renormalization and build-up of optical gain in monolayer MoTe$_2$. https://doi.org/10.1103/physrevb.101.075401

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