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arXiv · 1301.7266

Electronic structure and absorption spectrum of biexciton obtained by using exciton basis

Shiue-Yuan Shiau·Monique Combescot·Yia-Chung Chang
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Abstract

We approach the biexciton Schr\"{o}dinger equation not through the free-carrier basis as usually done, but through the free-exciton basis, exciton-exciton interactions being treated according to the recently developed composite boson many-body formalism which allows an exact handling of carrier exchange between excitons, as induced by the Pauli exclusion principle. We numerically solve the resulting biexciton Schr\"{o}dinger equation with the exciton levels restricted to the ground state and we derive the biexciton ground state as well as the bound and unbound excited states as a function of hole-to-electron mass ratio. The biexciton ground-state energy we find, agrees reasonably well with variational results. Next, we use the obtained biexciton wave functions to calculate optical absorption in the presence of a dilute exciton gas in quantum well. We find a small asymmetric peak with a characteristic low-energy tail, identified with the biexciton ground state, and a set of large peaks associated with biexciton unbound states, i.e., exciton-exciton scattering states.

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Shiue-Yuan Shiau, Monique Combescot, Yia-Chung Chang. 2013-01-30. Electronic structure and absorption spectrum of biexciton obtained by using exciton basis. https://doi.org/10.1016/j.aop.2013.06.006

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