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arXiv · 1202.3616

Dynamics of a single exciton in strongly correlated bilayers

Louk Rademaker·Kai Wu·Jan Zaanen
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Abstract

We formulated an effective theory for a single interlayer exciton in a bilayer quantum antiferromagnet, in the limit that the holon and doublon are strongly bound onto one interlayer rung by the Coulomb force. Upon using a rung linear spin wave approximation of the bilayer Heisenberg model, we calculated the spectral function of the exciton for a wide range of the interlayer Heisenberg coupling α=J_{\perp}/Jz. In the disordered phase at large α, a coherent quasiparticle peak appears representing free motion of the exciton in a spin singlet background. In the Néel phase, which applies to more realistic model parameters, a ladder spectrum arises due to Ising confinement of the exciton. The exciton spectrum is visible in measurements of the dielectric function, such as c-axis optical conductivity measurements.

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Louk Rademaker, Kai Wu, Jan Zaanen. 2013-06-20. Dynamics of a single exciton in strongly correlated bilayers. https://doi.org/10.1088/1367-2630%2F14%2F8%2F083040

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