Exciton condensations in thin film topological insulator

Abstract

We study the many-body physics in thin film topological band insulator, where the inter-edge Coulomb interaction can lead to an exciton condensation transition. We investigate the universality class of the exciton condensation quantum critical point. With different chemical potentials and interactions, the exciton condensation can belong to z = 2 mean field, or 3d XY, or Yukawa-Higgs universality classes. The interplay between exciton condensate and the time-reversal symmetry breaking is also discussed. Predictions of our work can be tested experimentally by tuning the chemical potentials on both surfaces of the thin film through gate voltage. We also show that all the analysis of the exciton condensate can be directly applied to a spin-triplet superconductor phase with attractive inter-edge interaction.

5 pages, 3 figures, published version

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Cited by in corpus (8)

• Electron-hole pairing in topological insulator thin film
• Lattice model for the surface states of a topological insulator with applications to magnetic and exciton instabilities
• Topological Excitonic Superfluids in Three Dimensions
• Nanosecond dynamics in intrinsic topological insulator ${\text{Bi}}_{2-x}{\text{Sb}}_x{\text{Se}}_3$ revealed by time-resolved optical reflectivity
• Inter-surface interaction via phonon in three-dimensional topological insulator
• Excitonic gap generation in thin-film topological insulators
• Gapped energy spectra around the Dirac node at the surface of a 3D topological insulator in the presence of the time-reversal symmetry
• Dynamical density response and collective modes of topological insulator ultra-thin films