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arXiv · 1605.06001

Role of Strain on the Coherent Properties of GaAs Excitons and Biexcitons

Brian L. Wilmer·Daniel Webber·Joseph M. Ashley·Kimberley C. Hall·Alan D. Bristow
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Abstract

Polarization-dependent two-dimensional Fourier-transform spectroscopy (2DFTS) is performed on excitons in strained bulk GaAs layers probing the coherent response for differing amounts of strain. Biaxial tensile strain lifts the degeneracy of heavy-hole (HH) and light-hole (LH) valence states, leading to an observed splitting of the associated excitons at low temperature. Increasing the strain increases the magnitude of the HH/LH exciton peak splitting, induces an asymmetry in the off-diagonal coherences, increases the difference in the HH and LH exciton homogenous linewidths, and increases the inhomogeneous broadening of both exciton species. All results arise from strain-induced variations in the local electronic environment, which is not uniform along the growth direction of the thin layers. For cross-linear polarized excitation, wherein excitonic signals give way to biexcitonic signals, the high-strain sample shows evidence of bound LH, HH, and mixed biexcitons.

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Brian L. Wilmer, Daniel Webber, Joseph M. Ashley, Kimberley C. Hall, Alan D. Bristow. 2016-05-19. Role of Strain on the Coherent Properties of GaAs Excitons and Biexcitons. https://doi.org/10.1103/physrevb.94.075207

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