Dynamics of a single exciton in strongly correlated bilayers
Abstract
We formulated an effective theory for a single interlayer exciton in a bilayer quantum antiferromagnet, in the limit when the holon and doublon are strongly bound onto one interlayer rung by the Coulomb force. Upon using a rung linear spinwave 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_{⊥}/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 caxis optical conductivity measurements.
 Publication:

New Journal of Physics
 Pub Date:
 August 2012
 DOI:
 10.1088/13672630/14/8/083040
 arXiv:
 arXiv:1202.3616
 Bibcode:
 2012NJPh...14h3040R
 Keywords:

 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 28 pages, 12 figures