Second-Order Josephson Effect in Excitonic Insulators.

  title={Second-Order Josephson Effect in Excitonic Insulators.},
  author={Zhiyuan Sun and Tatsuya Kaneko and Denis Gole{\vz} and Andrew J. Millis},
  journal={Physical review letters},
  volume={127 12},
We show that in electron-hole bilayers with excitonic orders arising from conduction and valence bands formed by atomic orbitals that have different parities, nonzero interlayer tunneling leads to a second-order Josephson effect. This means the interlayer electrical current is related to the phase of the excitonic order parameter as J=J_{c}sin2θ instead of J=J_{c}sinθ and that the system has two degenerate ground states at θ=0,π that can be switched by an interlayer voltage pulse. When… Expand
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